diff --git a/.github/workflows/mingw.yml b/.github/workflows/mingw.yml
new file mode 100644
index 00000000000000..69c034e05f54a6
--- /dev/null
+++ b/.github/workflows/mingw.yml
@@ -0,0 +1,319 @@
+name: Build
+on: [push, pull_request, workflow_dispatch]
+
+jobs:
+  build:
+    runs-on: ${{ matrix.runner }}
+    strategy:
+      fail-fast: false
+      matrix:
+        msystem: ['MINGW64','MINGW32','UCRT64','CLANG64','CLANGARM64']
+        include:
+          - msystem: MINGW64
+            prefix: mingw-w64-x86_64
+            runner: windows-2022
+          - msystem: MINGW32
+            prefix: mingw-w64-i686
+            runner: windows-2022
+          - msystem: UCRT64
+            prefix: mingw-w64-ucrt-x86_64
+            runner: windows-2022
+          - msystem: CLANG64
+            prefix: mingw-w64-clang-x86_64
+            runner: windows-2022
+          - msystem: CLANGARM64
+            prefix: mingw-w64-clang-aarch64
+            runner: windows-11-arm
+    steps:
+      - name: Setup git
+        run: |
+          git config --global core.autocrlf false
+          git config --global core.eol lf
+      - uses: actions/checkout@v4
+      - uses: msys2/setup-msys2@v2
+        with:
+          msystem: ${{ matrix.msystem }}
+          release: ${{ matrix.msystem == 'CLANGARM64' }}
+          update: true
+          install: >-
+            make
+            binutils
+            autoconf
+            autoconf-archive
+            automake-wrapper
+            tar
+            gzip
+            ${{ matrix.prefix }}-toolchain
+            ${{ matrix.prefix }}-expat
+            ${{ matrix.prefix }}-bzip2
+            ${{ matrix.prefix }}-libffi
+            ${{ matrix.prefix }}-mpdecimal
+            ${{ matrix.prefix }}-ncurses
+            ${{ matrix.prefix }}-openssl
+            ${{ matrix.prefix }}-sqlite3
+            ${{ matrix.prefix }}-tcl
+            ${{ matrix.prefix }}-tk
+            ${{ matrix.prefix }}-zlib
+            ${{ matrix.prefix }}-xz
+            ${{ matrix.prefix }}-tzdata
+
+      - name: Build Python
+        shell: msys2 {0}
+        run: |
+          set -ex
+
+          if [[ "${{ matrix.msystem }}" == CLANG* ]]; then
+            export CC=clang
+            export CXX=clang++
+          fi
+          autoreconf -vfi
+
+          rm -Rf _build && mkdir _build && cd _build
+
+          ../configure \
+            --prefix=${MINGW_PREFIX} \
+            --host=${MINGW_CHOST} \
+            --build=${MINGW_CHOST} \
+            --enable-shared \
+            --with-system-expat \
+            --with-system-libmpdec \
+            --without-ensurepip \
+            --enable-loadable-sqlite-extensions \
+            --with-tzpath=${MINGW_PREFIX}/share/zoneinfo \
+            --enable-optimizations
+
+          make -j8
+
+      - name: Run Smoke Test (build)
+        shell: msys2 {0}
+        run: |
+          SMOKETESTS="$(pwd)/mingw_smoketests.py"
+          cd _build
+          ./python.exe "$SMOKETESTS"
+          MSYSTEM= ./python.exe "$SMOKETESTS"
+
+      - name: Run tests
+        shell: msys2 {0}
+        run: |
+          IGNOREFILE="$(pwd)/mingw_ignorefile.txt"
+          IGNOREFILE_EXTRA="$IGNOREFILE"
+          if [[ "${{ matrix.msystem }}" == "MINGW32" ]] || [[ "${{ matrix.msystem }}" == "MINGW64" ]]; then
+            IGNOREFILE_EXTRA="$(pwd)/mingw_ignorefile_msvcrt.txt"
+          fi
+          cd _build
+          MSYSTEM= ./python.exe -m test -j8 --ignorefile "$IGNOREFILE" --ignorefile "$IGNOREFILE_EXTRA" -W
+
+      - name: Run broken tests
+        continue-on-error: true
+        shell: msys2 {0}
+        run: |
+          IGNOREFILE="$(pwd)/mingw_ignorefile.txt"
+          IGNOREFILE_EXTRA="$IGNOREFILE"
+          if [[ "${{ matrix.msystem }}" == "MINGW32" ]] || [[ "${{ matrix.msystem }}" == "MINGW64" ]]; then
+            IGNOREFILE_EXTRA="$(pwd)/mingw_ignorefile_msvcrt.txt"
+          fi
+          cd _build
+          MSYSTEM= ./python.exe -m test -j8 --matchfile "$IGNOREFILE" --matchfile "$IGNOREFILE_EXTRA" -W
+
+      - name: Install
+        shell: msys2 {0}
+        run: |
+          set -ex
+          cd _build
+
+          pkgdir=python_pkgdir
+
+          make -j1 install DESTDIR="${pkgdir}"
+
+          # Fix shebangs
+          _pybasever=$(./python.exe -c "import sys; print(f'{sys.version_info[0]}.{sys.version_info[1]}');")
+          for fscripts in 2to3 2to3-${_pybasever} idle3 idle${_pybasever} pydoc3 pydoc${_pybasever}; do
+              sed -i "s|$(cygpath -w ${MINGW_PREFIX} | sed 's|\\|\\\\|g')/bin/python${_pybasever}.exe|/usr/bin/env python${_pybasever}.exe|g" "${pkgdir}${MINGW_PREFIX}"/bin/${fscripts}
+          done
+          sed -i "s|#!${MINGW_PREFIX}/bin/python${_pybasever}.exe|#!/usr/bin/env python${_pybasever}.exe|" "${pkgdir}${MINGW_PREFIX}"/lib/python${_pybasever}/config-${_pybasever}/python-config.py
+
+          # Create version-less aliases
+          cp "${pkgdir}${MINGW_PREFIX}"/bin/python3.exe "${pkgdir}${MINGW_PREFIX}"/bin/python.exe
+          cp "${pkgdir}${MINGW_PREFIX}"/bin/python3w.exe "${pkgdir}${MINGW_PREFIX}"/bin/pythonw.exe
+          cp "${pkgdir}${MINGW_PREFIX}"/bin/python3-config "${pkgdir}${MINGW_PREFIX}"/bin/python-config
+          cp "${pkgdir}${MINGW_PREFIX}"/bin/idle3 "${pkgdir}${MINGW_PREFIX}"/bin/idle
+          cp "${pkgdir}${MINGW_PREFIX}"/bin/pydoc3 "${pkgdir}${MINGW_PREFIX}"/bin/pydoc
+
+          # copy to /
+          cp -rf "${pkgdir}"/* /
+
+      - name: Run Smoke Test (installed)
+        shell: msys2 {0}
+        run: |
+          SMOKETESTS="$(pwd)/mingw_smoketests.py"
+          ${MINGW_PREFIX}/bin/python.exe "$SMOKETESTS"
+          MSYSTEM= ${MINGW_PREFIX}/bin/python.exe "$SMOKETESTS"
+
+      - name: Compress
+        if: always()
+        shell: msys2 {0}
+        run: |
+          cd _build
+          tar -zcf python.tar.gz python_pkgdir/
+
+      - name: Upload
+        uses: actions/upload-artifact@v4
+        if: always()
+        with:
+          name: build-${{ matrix.msystem }}
+          path: _build/python.tar.gz
+
+  cross-gcc-x86_64:
+    runs-on: ubuntu-latest
+    container:
+      image: ubuntu:25.04
+    steps:
+      - uses: actions/checkout@v4
+      - name: Install deps
+        run: |
+          apt-get update
+          DEBIAN_FRONTEND=noninteractive apt-get install -y \
+            gcc-mingw-w64-x86-64 \
+            g++-mingw-w64-x86-64 \
+            autoconf-archive \
+            autoconf \
+            automake \
+            zip \
+            make \
+            pkg-config
+
+      - uses: actions/setup-python@v5
+        with:
+          python-version: '3.12'
+
+      - name: Check Python Version
+        run: |
+          which python
+          python --version
+
+      - name: Build
+        run: |
+          autoreconf -vfi
+
+          mkdir _build && cd _build
+
+          export PKG_CONFIG_LIBDIR=/dev/null
+          unset PKG_CONFIG_PATH
+
+          ../configure \
+            --host=x86_64-w64-mingw32 \
+            --build=x86_64-pc-linux-gnu \
+            --enable-shared \
+            --without-ensurepip \
+            --enable-loadable-sqlite-extensions \
+            --with-build-python=yes
+
+          make -j8
+
+          make install DESTDIR="$(pwd)/install"
+
+      - name: 'Zip files'
+        run: |
+          zip -r install.zip _build/install
+
+      - name: Upload
+        uses: actions/upload-artifact@v4
+        with:
+          name: build-cross-gcc-x86_64
+          path: install.zip
+
+  cross-gcc-x86_64-test:
+    needs: [cross-gcc-x86_64]
+    runs-on: windows-latest
+    steps:
+      - uses: actions/download-artifact@v4
+        with:
+          name: build-cross-gcc-x86_64
+
+      - name: 'Run tests'
+        run: |
+          7z x install.zip
+          ./_build/install/usr/local/bin/python3.exe -c "import sysconfig, pprint; pprint.pprint(sysconfig.get_config_vars())"
+
+
+  cross-llvm-mingw:
+    runs-on: ubuntu-latest
+    container:
+      image: mstorsjo/llvm-mingw:latest
+    strategy:
+      fail-fast: false
+      matrix:
+        arch: ['x86_64', 'i686', 'aarch64', 'armv7']
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Install deps
+        run: |
+          export DEBIAN_FRONTEND=noninteractive
+          apt-get update -qq
+          apt-get install -qqy software-properties-common
+          add-apt-repository --yes ppa:deadsnakes/ppa
+          apt-get update -qq
+          apt-get install -qqy autoconf-archive python3.12-dev python3.12
+
+      - name: Build
+        run: |
+          autoreconf -vfi
+
+          mkdir _build && cd _build
+
+          export PKG_CONFIG_LIBDIR=/dev/null
+          unset PKG_CONFIG_PATH
+
+          export CC=${{ matrix.arch }}-w64-mingw32-clang
+          export CXX=${CC}++
+          ../configure \
+            --host=${{ matrix.arch }}-w64-mingw32 \
+            --build=x86_64-pc-linux-gnu \
+            --enable-shared \
+            --without-ensurepip \
+            --without-c-locale-coercion \
+            --enable-loadable-sqlite-extensions \
+            --with-build-python=yes
+
+          make -j8
+
+          make install DESTDIR="$(pwd)/install"
+
+      - name: 'Zip files'
+        run: |
+          zip -r install.zip _build/install
+
+      - name: Upload
+        uses: actions/upload-artifact@v4
+        with:
+          name: build-cross-llvm-mingw-${{ matrix.arch }}
+          path: install.zip
+
+  cross-llvm-mingw-test:
+    needs: [cross-llvm-mingw]
+    runs-on: ${{ matrix.runner }}
+    strategy:
+      fail-fast: false
+      matrix:
+        arch: ['x86_64', 'i686', 'aarch64']
+        include:
+          - arch: x86_64
+            runner: windows-latest
+          - arch: i686
+            runner: windows-latest
+          - arch: aarch64
+            runner: windows-11-arm
+    steps:
+      - uses: actions/download-artifact@v4
+        with:
+          name: build-cross-llvm-mingw-${{ matrix.arch }}
+
+      - name: 'Run tests'
+        run: |
+          if (Test-Path ./_build) {rm -r -fo ./_build}
+          Add-Type -AssemblyName System.IO.Compression.FileSystem ;
+          [System.IO.Compression.ZipFile]::ExtractToDirectory("$PWD\install.zip", "$PWD")
+          ./_build/install/usr/local/bin/python3.exe -c "import sysconfig, pprint; pprint.pprint(sysconfig.get_config_vars())"
+
+
diff --git a/Include/bytesobject.h b/Include/bytesobject.h
index ee448cd02bdab3..d10ec3f86cb696 100644
--- a/Include/bytesobject.h
+++ b/Include/bytesobject.h
@@ -35,9 +35,9 @@ PyAPI_FUNC(PyObject *) PyBytes_FromStringAndSize(const char *, Py_ssize_t);
 PyAPI_FUNC(PyObject *) PyBytes_FromString(const char *);
 PyAPI_FUNC(PyObject *) PyBytes_FromObject(PyObject *);
 PyAPI_FUNC(PyObject *) PyBytes_FromFormatV(const char*, va_list)
-                                Py_GCC_ATTRIBUTE((format(printf, 1, 0)));
+                                Py_PRINTF(1, 0);
 PyAPI_FUNC(PyObject *) PyBytes_FromFormat(const char*, ...)
-                                Py_GCC_ATTRIBUTE((format(printf, 1, 2)));
+                                Py_PRINTF(1, 2);
 PyAPI_FUNC(Py_ssize_t) PyBytes_Size(PyObject *);
 PyAPI_FUNC(char *) PyBytes_AsString(PyObject *);
 PyAPI_FUNC(PyObject *) PyBytes_Repr(PyObject *, int);
diff --git a/Include/fileobject.h b/Include/fileobject.h
index 2deef544d667a5..ae4bdac2edcf97 100644
--- a/Include/fileobject.h
+++ b/Include/fileobject.h
@@ -30,7 +30,7 @@ Py_DEPRECATED(3.12) PyAPI_DATA(int) Py_UTF8Mode;
 #endif
 
 /* A routine to check if a file descriptor can be select()-ed. */
-#ifdef _MSC_VER
+#ifdef MS_WINDOWS
     /* On Windows, any socket fd can be select()-ed, no matter how high */
     #define _PyIsSelectable_fd(FD) (1)
 #else
diff --git a/Include/internal/pycore_condvar.h b/Include/internal/pycore_condvar.h
index 2177bed31fcd27..c46486f0947b8d 100644
--- a/Include/internal/pycore_condvar.h
+++ b/Include/internal/pycore_condvar.h
@@ -5,6 +5,12 @@
 #  error "this header requires Py_BUILD_CORE define"
 #endif
 
+#ifdef __MINGW32__
+# if !defined(HAVE_PTHREAD_H) || defined(NT_THREADS)
+#  undef _POSIX_THREADS
+# endif
+#endif
+
 #ifndef _POSIX_THREADS
 /* This means pthreads are not implemented in libc headers, hence the macro
    not present in unistd.h. But they still can be implemented as an external
@@ -41,6 +47,10 @@
 #  define WIN32_LEAN_AND_MEAN
 #endif
 #include <windows.h>              // CRITICAL_SECTION
+/* winpthreads are involved via windows header, so need undef _POSIX_THREADS after header include */
+#if defined(_POSIX_THREADS)
+#undef _POSIX_THREADS
+#endif
 
 /* options */
 /* non-emulated condition variables are provided for those that want
diff --git a/Include/iscygpty.h b/Include/iscygpty.h
new file mode 100644
index 00000000000000..82fd0affbd4875
--- /dev/null
+++ b/Include/iscygpty.h
@@ -0,0 +1,41 @@
+/*
+ * iscygpty.h -- part of ptycheck
+ * https://github.com/k-takata/ptycheck
+ *
+ * Copyright (c) 2015-2017 K.Takata
+ *
+ * You can redistribute it and/or modify it under the terms of either
+ * the MIT license (as described below) or the Vim license.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+ * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+ * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#ifndef _ISCYGPTY_H
+#define _ISCYGPTY_H
+
+#ifdef _WIN32
+int is_cygpty(int fd);
+int is_cygpty_used(void);
+#else
+#define is_cygpty(fd)		0
+#define is_cygpty_used()	0
+#endif
+
+#endif /* _ISCYGPTY_H */
diff --git a/Include/osdefs.h b/Include/osdefs.h
index 3243944a1483e9..99d49777a69d9a 100644
--- a/Include/osdefs.h
+++ b/Include/osdefs.h
@@ -10,7 +10,6 @@ extern "C" {
 #ifdef MS_WINDOWS
 #define SEP L'\\'
 #define ALTSEP L'/'
-#define MAXPATHLEN 256
 #define DELIM L';'
 #endif
 
diff --git a/Include/py_curses.h b/Include/py_curses.h
index e46b08e9cc414e..34228fbba55c81 100644
--- a/Include/py_curses.h
+++ b/Include/py_curses.h
@@ -36,6 +36,13 @@
 #include <curses.h>
 #endif
 
+#if defined(__MINGW32__)
+#include <windows.h>
+#if !defined(_ISPAD)
+#define _ISPAD 0x10
+#endif
+#endif
+
 #ifdef HAVE_NCURSES_H
 /* configure was checking <curses.h>, but we will
    use <ncurses.h>, which has some or all these features. */
diff --git a/Include/pyerrors.h b/Include/pyerrors.h
index d089fa71779330..f8e604eef546e8 100644
--- a/Include/pyerrors.h
+++ b/Include/pyerrors.h
@@ -321,9 +321,9 @@ PyAPI_FUNC(int) PyUnicodeTranslateError_SetReason(
     );
 
 PyAPI_FUNC(int) PyOS_snprintf(char *str, size_t size, const char  *format, ...)
-                        Py_GCC_ATTRIBUTE((format(printf, 3, 4)));
+                        Py_PRINTF(3, 4);
 PyAPI_FUNC(int) PyOS_vsnprintf(char *str, size_t size, const char  *format, va_list va)
-                        Py_GCC_ATTRIBUTE((format(printf, 3, 0)));
+                        Py_PRINTF(3, 0);
 
 #ifndef Py_LIMITED_API
 #  define Py_CPYTHON_ERRORS_H
diff --git a/Include/pylifecycle.h b/Include/pylifecycle.h
index e4c3b09c963fe8..21346baf73e2ca 100644
--- a/Include/pylifecycle.h
+++ b/Include/pylifecycle.h
@@ -21,6 +21,15 @@ PyAPI_FUNC(int) Py_IsInitialized(void);
 PyAPI_FUNC(PyThreadState *) Py_NewInterpreter(void);
 PyAPI_FUNC(void) Py_EndInterpreter(PyThreadState *);
 
+PyAPI_FUNC(wchar_t) Py_GetAltSepW(const wchar_t *);
+PyAPI_FUNC(wchar_t) Py_GetSepW(const wchar_t *);
+PyAPI_FUNC(char) Py_GetSepA(const char *);
+
+PyAPI_FUNC(void) Py_NormalizeSepsW(wchar_t *);
+PyAPI_FUNC(void) Py_NormalizeSepsA(char *);
+
+PyAPI_FUNC(void) Py_NormalizeSepsPathcchW(wchar_t *);
+
 
 /* Py_PyAtExit is for the atexit module, Py_AtExit is for low-level
  * exit functions.
diff --git a/Include/pyport.h b/Include/pyport.h
index e2bac3bf504261..df363d0daa2dbd 100644
--- a/Include/pyport.h
+++ b/Include/pyport.h
@@ -53,6 +53,44 @@
 #endif
 
 
+#ifdef __MINGW32__
+/* Translate GCC[mingw*] platform specific defines to those
+ * used in python code.
+ */
+#if !defined(MS_WIN64) && defined(_WIN64)
+#  define MS_WIN64
+#endif
+#if !defined(MS_WIN32) && defined(_WIN32)
+#  define MS_WIN32
+#endif
+#if !defined(MS_WINDOWS) && defined(MS_WIN32)
+#  define MS_WINDOWS
+#endif
+
+#if defined(Py_BUILD_CORE) || defined(Py_BUILD_CORE_BUILTIN) || defined(Py_BUILD_CORE_MODULE)
+#include <winapifamily.h>
+
+#if WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP)
+#define MS_WINDOWS_DESKTOP
+#endif
+#if WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_APP)
+#define MS_WINDOWS_APP
+#endif
+#if WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_SYSTEM)
+#define MS_WINDOWS_SYSTEM
+#endif
+#if WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_GAMES)
+#define MS_WINDOWS_GAMES
+#endif
+
+/* Define to 1 if you support windows console io */
+#if defined(MS_WINDOWS_DESKTOP) || defined(MS_WINDOWS_APP) || defined(MS_WINDOWS_SYSTEM)
+#define HAVE_WINDOWS_CONSOLE_IO 1
+#endif
+#endif /* Py_BUILD_CORE || Py_BUILD_CORE_BUILTIN || Py_BUILD_CORE_MODULE */
+
+#endif /* __MINGW32__*/
+
 /**************************************************************************
 Symbols and macros to supply platform-independent interfaces to basic
 C language & library operations whose spellings vary across platforms.
@@ -494,12 +532,12 @@ extern char * _getpty(int *, int, mode_t, int);
 */
 
 /*
-  All windows ports, except cygwin, are handled in PC/pyconfig.h.
+  Only MSVC windows ports is handled in PC/pyconfig.h.
 
-  Cygwin is the only other autoconf platform requiring special
+  Cygwin and Mingw is the only other autoconf platform requiring special
   linkage handling and it uses __declspec().
 */
-#if defined(__CYGWIN__)
+#if defined(__CYGWIN__) || defined(__MINGW32__)
 #       define HAVE_DECLSPEC_DLL
 #endif
 
@@ -512,21 +550,23 @@ extern char * _getpty(int *, int, mode_t, int);
 #                       define PyAPI_FUNC(RTYPE) Py_EXPORTED_SYMBOL RTYPE
 #                       define PyAPI_DATA(RTYPE) extern Py_EXPORTED_SYMBOL RTYPE
         /* module init functions inside the core need no external linkage */
-        /* except for Cygwin to handle embedding */
-#                       if defined(__CYGWIN__)
+        /* except for Cygwin/Mingw to handle embedding */
+#                       if defined(__CYGWIN__) || defined(__MINGW32__)
 #                               define PyMODINIT_FUNC Py_EXPORTED_SYMBOL PyObject*
-#                       else /* __CYGWIN__ */
+#                       else /* __CYGWIN__ || __MINGW32__*/
 #                               define PyMODINIT_FUNC PyObject*
-#                       endif /* __CYGWIN__ */
+#                       endif /* __CYGWIN__ || __MINGW32__*/
 #               else /* Py_BUILD_CORE */
         /* Building an extension module, or an embedded situation */
         /* public Python functions and data are imported */
         /* Under Cygwin, auto-import functions to prevent compilation */
         /* failures similar to those described at the bottom of 4.1: */
         /* http://docs.python.org/extending/windows.html#a-cookbook-approach */
-#                       if !defined(__CYGWIN__)
+#                       if defined(__CYGWIN__) || defined(__MINGW32__)
+#                               define PyAPI_FUNC(RTYPE) RTYPE
+#                       else
 #                               define PyAPI_FUNC(RTYPE) Py_IMPORTED_SYMBOL RTYPE
-#                       endif /* !__CYGWIN__ */
+#                       endif /* __CYGWIN__ || __MINGW32__*/
 #                       define PyAPI_DATA(RTYPE) extern Py_IMPORTED_SYMBOL RTYPE
         /* module init functions outside the core must be exported */
 #                       if defined(__cplusplus)
@@ -626,6 +666,12 @@ extern char * _getpty(int *, int, mode_t, int);
 
 #define Py_VA_COPY va_copy
 
+#if defined(__GNUC__) && ((__GNUC__ == 4 && __GNUC_MINOR__>= 4) || __GNUC__ > 4)
+#  define Py_PRINTF(X,Y) Py_GCC_ATTRIBUTE((format(gnu_printf,X,Y)))
+#else
+#  define Py_PRINTF(X,Y) Py_GCC_ATTRIBUTE((format(printf,X,Y))) 
+#endif
+
 /*
  * Convenient macros to deal with endianness of the platform. WORDS_BIGENDIAN is
  * detected by configure and defined in pyconfig.h. The code in pyconfig.h
diff --git a/Include/pythread.h b/Include/pythread.h
index 63714437c496b7..5e84e3cbefc330 100644
--- a/Include/pythread.h
+++ b/Include/pythread.h
@@ -7,6 +7,12 @@ typedef void *PyThread_type_lock;
 extern "C" {
 #endif
 
+#ifdef __MINGW32__
+# if !defined(HAVE_PTHREAD_H) || defined(NT_THREADS)
+#  undef _POSIX_THREADS
+# endif
+#endif
+
 /* Return status codes for Python lock acquisition.  Chosen for maximum
  * backwards compatibility, ie failure -> 0, success -> 1.  */
 typedef enum PyLockStatus {
diff --git a/Include/sysmodule.h b/Include/sysmodule.h
index 96f883870b34dc..55c558a9037b8e 100644
--- a/Include/sysmodule.h
+++ b/Include/sysmodule.h
@@ -15,9 +15,9 @@ Py_DEPRECATED(3.11) PyAPI_FUNC(void) PySys_SetArgvEx(int, wchar_t **, int);
 Py_DEPRECATED(3.11) PyAPI_FUNC(void) PySys_SetPath(const wchar_t *);
 
 PyAPI_FUNC(void) PySys_WriteStdout(const char *format, ...)
-                 Py_GCC_ATTRIBUTE((format(printf, 1, 2)));
+                 Py_PRINTF(1, 2);
 PyAPI_FUNC(void) PySys_WriteStderr(const char *format, ...)
-                 Py_GCC_ATTRIBUTE((format(printf, 1, 2)));
+                 Py_PRINTF(1, 2);
 PyAPI_FUNC(void) PySys_FormatStdout(const char *format, ...);
 PyAPI_FUNC(void) PySys_FormatStderr(const char *format, ...);
 
diff --git a/Lib/compileall.py b/Lib/compileall.py
index d394156cedc4e7..ef3633e9537615 100644
--- a/Lib/compileall.py
+++ b/Lib/compileall.py
@@ -38,6 +38,8 @@ def _walk_dir(dir, maxlevels, quiet=0):
         if name == '__pycache__':
             continue
         fullname = os.path.join(dir, name)
+        if sys.platform == "win32" and sys.version.find("GCC") >= 0:
+            fullname = fullname.replace('\\','/')
         if not os.path.isdir(fullname):
             yield fullname
         elif (maxlevels > 0 and name != os.curdir and name != os.pardir and
diff --git a/Lib/ctypes/__init__.py b/Lib/ctypes/__init__.py
index 6cedee74236ea5..7fceeb8fa4e320 100644
--- a/Lib/ctypes/__init__.py
+++ b/Lib/ctypes/__init__.py
@@ -464,7 +464,9 @@ def LoadLibrary(self, name):
 cdll = LibraryLoader(CDLL)
 pydll = LibraryLoader(PyDLL)
 
-if _os.name == "nt":
+if _os.name == "nt" and _sys.version.find('GCC') >= 0:
+    pythonapi = PyDLL("libpython%d.%d%s.dll" % (_sys.version_info[:2] + (_sys.abiflags,)), None)
+elif _os.name == "nt":
     pythonapi = PyDLL("python dll", None, _sys.dllhandle)
 elif _sys.platform == "cygwin":
     pythonapi = PyDLL("libpython%d.%d.dll" % _sys.version_info[:2])
diff --git a/Lib/ctypes/util.py b/Lib/ctypes/util.py
index c550883e7c7d4b..a5a2a3f5dc2d9d 100644
--- a/Lib/ctypes/util.py
+++ b/Lib/ctypes/util.py
@@ -31,6 +31,12 @@ def _get_build_version():
         # else we don't know what version of the compiler this is
         return None
 
+    def find_msvcrt_mingw():
+        is_ucrt = 'clang' in sys.version.lower() or 'ucrt' in sys.version.lower()
+        if is_ucrt:
+            return None
+        return 'msvcrt.dll'
+
     def find_msvcrt():
         """Return the name of the VC runtime dll"""
         version = _get_build_version()
@@ -54,6 +60,9 @@ def find_msvcrt():
 
     def find_library(name):
         if name in ('c', 'm'):
+            import sysconfig
+            if sysconfig.get_platform().startswith('mingw'):
+                return find_msvcrt_mingw()
             return find_msvcrt()
         # See MSDN for the REAL search order.
         for directory in os.environ['PATH'].split(os.pathsep):
diff --git a/Lib/importlib/_bootstrap_external.py b/Lib/importlib/_bootstrap_external.py
index 9b8a8dfc5aae28..a177fa72cfd1c3 100644
--- a/Lib/importlib/_bootstrap_external.py
+++ b/Lib/importlib/_bootstrap_external.py
@@ -42,6 +42,10 @@
     path_separators = ['\\', '/']
 else:
     path_separators = ['/']
+
+if _os.environ.get('MSYSTEM', ''):
+    path_separators = path_separators[::-1]
+
 # Assumption made in _path_join()
 assert all(len(sep) == 1 for sep in path_separators)
 path_sep = path_separators[0]
diff --git a/Lib/ntpath.py b/Lib/ntpath.py
index 1bef630bd9c0ff..15830f903b8050 100644
--- a/Lib/ntpath.py
+++ b/Lib/ntpath.py
@@ -11,9 +11,7 @@
 curdir = '.'
 pardir = '..'
 extsep = '.'
-sep = '\\'
 pathsep = ';'
-altsep = '/'
 defpath = '.;C:\\bin'
 devnull = 'nul'
 
@@ -23,6 +21,14 @@
 import genericpath
 from genericpath import *
 
+if sys.platform == "win32" and os.environ.get("MSYSTEM", ""):
+    sep = '/'
+    altsep = '\\'
+else:
+    sep = '\\'
+    altsep = '/'
+bsep = str.encode(sep)
+baltsep = str.encode(altsep)
 
 __all__ = ["normcase","isabs","join","splitdrive","splitroot","split","splitext",
            "basename","dirname","commonprefix","getsize","getmtime",
@@ -35,9 +41,33 @@
 
 def _get_bothseps(path):
     if isinstance(path, bytes):
-        return b'\\/'
+        return bsep+baltsep
+    else:
+        return sep+altsep
+
+def _get_sep(path):
+    if isinstance(path, bytes):
+        return bsep
+    else:
+        return sep
+
+def _get_altsep(path):
+    if isinstance(path, bytes):
+        return baltsep
+    else:
+        return altsep
+
+def _get_colon(path):
+    if isinstance(path, bytes):
+        return b':'
+    else:
+        return ':'
+
+def _get_unc_prefix(path):
+    if isinstance(path, bytes):
+        return b'\\\\?\\UNC\\'
     else:
-        return '\\/'
+        return '\\\\?\\UNC\\'
 
 # Normalize the case of a pathname and map slashes to backslashes.
 # Other normalizations (such as optimizing '../' away) are not done
@@ -59,14 +89,14 @@ def normcase(s):
             return s
         if isinstance(s, bytes):
             encoding = sys.getfilesystemencoding()
-            s = s.decode(encoding, 'surrogateescape').replace('/', '\\')
+            s = s.decode(encoding, 'surrogateescape').replace(altsep, sep)
             s = _LCMapStringEx(_LOCALE_NAME_INVARIANT,
                                _LCMAP_LOWERCASE, s)
             return s.encode(encoding, 'surrogateescape')
         else:
             return _LCMapStringEx(_LOCALE_NAME_INVARIANT,
                                   _LCMAP_LOWERCASE,
-                                  s.replace('/', '\\'))
+                                  s.replace(altsep, sep))
 except ImportError:
     def normcase(s):
         """Normalize case of pathname.
@@ -75,8 +105,8 @@ def normcase(s):
         """
         s = os.fspath(s)
         if isinstance(s, bytes):
-            return os.fsencode(os.fsdecode(s).replace('/', '\\').lower())
-        return s.replace('/', '\\').lower()
+            return os.fsencode(os.fsdecode(s).replace(altsep, sep).lower())
+        return s.replace(altsep, sep).lower()
 
 
 # Return whether a path is absolute.
@@ -88,14 +118,9 @@ def normcase(s):
 def isabs(s):
     """Test whether a path is absolute"""
     s = os.fspath(s)
-    if isinstance(s, bytes):
-        sep = b'\\'
-        altsep = b'/'
-        colon_sep = b':\\'
-    else:
-        sep = '\\'
-        altsep = '/'
-        colon_sep = ':\\'
+    sep = _get_sep(s)
+    altsep = _get_altsep(s)
+    colon_sep = _get_colon(s) + sep
     s = s[:3].replace(altsep, sep)
     # Absolute: UNC, device, and paths with a drive and root.
     # LEGACY BUG: isabs("/x") should be false since the path has no drive.
@@ -107,14 +132,9 @@ def isabs(s):
 # Join two (or more) paths.
 def join(path, *paths):
     path = os.fspath(path)
-    if isinstance(path, bytes):
-        sep = b'\\'
-        seps = b'\\/'
-        colon = b':'
-    else:
-        sep = '\\'
-        seps = '\\/'
-        colon = ':'
+    sep = _get_sep(path)
+    seps = _get_bothseps(path)
+    colon = _get_colon(path)
     try:
         if not paths:
             path[:0] + sep  #23780: Ensure compatible data type even if p is null.
@@ -189,18 +209,12 @@ def splitroot(p):
         splitroot('Windows/notepad') == ('', '', 'Windows/notepad')
     """
     p = os.fspath(p)
-    if isinstance(p, bytes):
-        sep = b'\\'
-        altsep = b'/'
-        colon = b':'
-        unc_prefix = b'\\\\?\\UNC\\'
-        empty = b''
-    else:
-        sep = '\\'
-        altsep = '/'
-        colon = ':'
-        unc_prefix = '\\\\?\\UNC\\'
-        empty = ''
+    sep = _get_sep(p)
+    altsep = _get_altsep(p)
+    colon = _get_colon(p)
+    unc_prefix = _get_unc_prefix(p)
+    empty = b'' if isinstance(p, bytes) else ''
+
     normp = p.replace(altsep, sep)
     if normp[:1] == sep:
         if normp[1:2] == sep:
@@ -258,9 +272,9 @@ def split(p):
 def splitext(p):
     p = os.fspath(p)
     if isinstance(p, bytes):
-        return genericpath._splitext(p, b'\\', b'/', b'.')
+        return genericpath._splitext(p, bsep, baltsep, b'.')
     else:
-        return genericpath._splitext(p, '\\', '/', '.')
+        return genericpath._splitext(p, sep, altsep, '.')
 splitext.__doc__ = genericpath._splitext.__doc__
 
 
@@ -366,7 +380,7 @@ def expanduser(path):
     if 'USERPROFILE' in os.environ:
         userhome = os.environ['USERPROFILE']
     elif not 'HOMEPATH' in os.environ:
-        return path
+        return os.path.normpath(path)
     else:
         try:
             drive = os.environ['HOMEDRIVE']
@@ -393,7 +407,7 @@ def expanduser(path):
     if isinstance(path, bytes):
         userhome = os.fsencode(userhome)
 
-    return userhome + path[i:]
+    return os.path.normpath(userhome) + path[i:]
 
 
 # Expand paths containing shell variable substitutions.
@@ -528,14 +542,12 @@ def expandvars(path):
     def normpath(path):
         """Normalize path, eliminating double slashes, etc."""
         path = os.fspath(path)
+        sep = _get_sep(path)
+        altsep = _get_altsep(path)
         if isinstance(path, bytes):
-            sep = b'\\'
-            altsep = b'/'
             curdir = b'.'
             pardir = b'..'
         else:
-            sep = '\\'
-            altsep = '/'
             curdir = '.'
             pardir = '..'
         path = path.replace(altsep, sep)
@@ -582,7 +594,7 @@ def abspath(path):
     def abspath(path):
         """Return the absolute version of a path."""
         try:
-            return _getfullpathname(normpath(path))
+            return normpath(_getfullpathname(normpath(path)))
         except (OSError, ValueError):
             # See gh-75230, handle outside for cleaner traceback
             pass
@@ -773,6 +785,7 @@ def realpath(path, *, strict=False):
                 # strip the prefix anyway.
                 if ex.winerror == initial_winerror:
                     path = spath
+        path = normpath(path)
         return path
 
 
@@ -782,12 +795,11 @@ def realpath(path, *, strict=False):
 def relpath(path, start=None):
     """Return a relative version of a path"""
     path = os.fspath(path)
+    sep = _get_sep(path)
     if isinstance(path, bytes):
-        sep = b'\\'
         curdir = b'.'
         pardir = b'..'
     else:
-        sep = '\\'
         curdir = '.'
         pardir = '..'
 
@@ -842,13 +854,11 @@ def commonpath(paths):
         raise ValueError('commonpath() arg is an empty sequence')
 
     paths = tuple(map(os.fspath, paths))
+    sep = _get_sep(paths[0])
+    altsep = _get_altsep(paths[0])
     if isinstance(paths[0], bytes):
-        sep = b'\\'
-        altsep = b'/'
         curdir = b'.'
     else:
-        sep = '\\'
-        altsep = '/'
         curdir = '.'
 
     try:
diff --git a/Lib/site.py b/Lib/site.py
index aed254ad504d35..16c7c41cd3d0c6 100644
--- a/Lib/site.py
+++ b/Lib/site.py
@@ -89,6 +89,12 @@
 USER_BASE = None
 
 
+# Same as defined in Lib/sysconfig.py
+# redeclared since sysconfig is large for site.
+# GCC[mingw*] use posix build system
+_POSIX_BUILD = os.name == 'posix' or \
+    (os.name == "nt" and 'GCC' in sys.version)
+
 def _trace(message):
     if sys.flags.verbose:
         print(message, file=sys.stderr)
@@ -294,7 +300,7 @@ def _getuserbase():
     def joinuser(*args):
         return os.path.expanduser(os.path.join(*args))
 
-    if os.name == "nt":
+    if os.name == "nt" and not _POSIX_BUILD:
         base = os.environ.get("APPDATA") or "~"
         return joinuser(base, "Python")
 
@@ -304,14 +310,42 @@ def joinuser(*args):
 
     return joinuser("~", ".local")
 
+# Copy of sysconfig.get_platform() but only for MinGW
+def _get_platform():
+    if os.name == 'nt':
+        if 'gcc' in sys.version.lower():
+            platform = 'mingw'
+            if 'amd64' in sys.version.lower():
+                platform += '_x86_64'
+            elif 'arm64' in sys.version.lower():
+                platform += '_aarch64'
+            elif 'arm' in sys.version.lower():
+                platform += '_armv7'
+            else:
+                platform += '_i686'
+
+            if 'ucrt' in sys.version.lower():
+                platform += '_ucrt'
+            else:
+                platform += "_msvcrt"
+
+            if 'clang' in sys.version.lower():
+                platform += "_llvm"
+            else:
+                platform += "_gnu"
+            
+            return platform
+    return sys.platform
 
 # Same to sysconfig.get_path('purelib', os.name+'_user')
 def _get_path(userbase):
     version = sys.version_info
 
     if os.name == 'nt':
-        ver_nodot = sys.winver.replace('.', '')
-        return f'{userbase}\\Python{ver_nodot}\\site-packages'
+        if not _POSIX_BUILD:
+            ver_nodot = sys.winver.replace('.', '')
+            return f'{userbase}\\Python{ver_nodot}\\site-packages'
+        return f'{userbase}/lib/python{version[0]}.{version[1]}-{_get_platform()}/site-packages'
 
     if sys.platform == 'darwin' and sys._framework:
         return f'{userbase}/lib/python/site-packages'
@@ -382,7 +416,7 @@ def getsitepackages(prefixes=None):
             continue
         seen.add(prefix)
 
-        if os.sep == '/':
+        if _POSIX_BUILD:
             libdirs = [sys.platlibdir]
             if sys.platlibdir != "lib":
                 libdirs.append("lib")
@@ -413,7 +447,7 @@ def setquit():
     The repr of each object contains a hint at how it works.
 
     """
-    if os.sep == '\\':
+    if sys.platform == 'win32':
         eof = 'Ctrl-Z plus Return'
     else:
         eof = 'Ctrl-D (i.e. EOF)'
diff --git a/Lib/ssl.py b/Lib/ssl.py
index 42ebb8ed38466d..791d5c548abe9c 100644
--- a/Lib/ssl.py
+++ b/Lib/ssl.py
@@ -254,7 +254,7 @@ class _TLSMessageType:
     CHANGE_CIPHER_SPEC = 0x0101
 
 
-if sys.platform == "win32":
+if sys.platform == "win32" and sys.version.find("GCC") == -1:
     from _ssl import enum_certificates, enum_crls
 
 from socket import socket, SOCK_STREAM, create_connection
@@ -528,7 +528,7 @@ def _load_windows_store_certs(self, storename, purpose):
     def load_default_certs(self, purpose=Purpose.SERVER_AUTH):
         if not isinstance(purpose, _ASN1Object):
             raise TypeError(purpose)
-        if sys.platform == "win32":
+        if sys.platform == "win32" and sys.version.find("GCC") == -1:
             for storename in self._windows_cert_stores:
                 self._load_windows_store_certs(storename, purpose)
         self.set_default_verify_paths()
diff --git a/Lib/sysconfig.py b/Lib/sysconfig.py
index acc8d4d1826b8a..c12ce38dec5b3d 100644
--- a/Lib/sysconfig.py
+++ b/Lib/sysconfig.py
@@ -2,6 +2,7 @@
 
 import os
 import sys
+import textwrap
 import threading
 from os.path import realpath
 
@@ -48,13 +49,13 @@
         'data': '{base}',
         },
     'nt': {
-        'stdlib': '{installed_base}/Lib',
-        'platstdlib': '{base}/Lib',
-        'purelib': '{base}/Lib/site-packages',
-        'platlib': '{base}/Lib/site-packages',
-        'include': '{installed_base}/Include',
-        'platinclude': '{installed_base}/Include',
-        'scripts': '{base}/Scripts',
+        'stdlib': '{installed_base}/lib/python{py_version_short}',
+        'platstdlib': '{base}/lib/python{py_version_short}',
+        'purelib': '{base}/lib/python{py_version_short}/site-packages',
+        'platlib': '{base}/lib/python{py_version_short}/site-packages',
+        'include': '{installed_base}/include/python{py_version_short}',
+        'platinclude': '{installed_base}/include/python{py_version_short}',
+        'scripts': '{base}/bin',
         'data': '{base}',
         },
     # Downstream distributors can overwrite the default install scheme.
@@ -98,13 +99,18 @@
         },
     }
 
+# GCC[mingw*] use posix build system
+_POSIX_BUILD = os.name == 'posix' or \
+    (os.name == "nt" and 'GCC' in sys.version)
+
 # For the OS-native venv scheme, we essentially provide an alias:
-if os.name == 'nt':
+if os.name == 'nt' and not _POSIX_BUILD:
     _INSTALL_SCHEMES['venv'] = _INSTALL_SCHEMES['nt_venv']
 else:
     _INSTALL_SCHEMES['venv'] = _INSTALL_SCHEMES['posix_venv']
 
 
+
 # NOTE: site.py has copy of this function.
 # Sync it when modify this function.
 def _getuserbase():
@@ -119,7 +125,7 @@ def _getuserbase():
     def joinuser(*args):
         return os.path.expanduser(os.path.join(*args))
 
-    if os.name == "nt":
+    if os.name == "nt" and not _POSIX_BUILD:
         base = os.environ.get("APPDATA") or "~"
         return joinuser(base, "Python")
 
@@ -135,20 +141,20 @@ def joinuser(*args):
     _INSTALL_SCHEMES |= {
         # NOTE: When modifying "purelib" scheme, update site._get_path() too.
         'nt_user': {
-            'stdlib': '{userbase}/Python{py_version_nodot_plat}',
-            'platstdlib': '{userbase}/Python{py_version_nodot_plat}',
-            'purelib': '{userbase}/Python{py_version_nodot_plat}/site-packages',
-            'platlib': '{userbase}/Python{py_version_nodot_plat}/site-packages',
-            'include': '{userbase}/Python{py_version_nodot_plat}/Include',
-            'scripts': '{userbase}/Python{py_version_nodot_plat}/Scripts',
+            'stdlib': '{userbase}/lib/python{py_version_short_plat}',
+            'platstdlib': '{userbase}/lib/python{py_version_short_plat}',
+            'purelib': '{userbase}/lib/python{py_version_short_plat}/site-packages',
+            'platlib': '{userbase}/lib/python{py_version_short_plat}/site-packages',
+            'include': '{userbase}/include/python{py_version_short_plat}',
+            'scripts': '{userbase}/bin',
             'data': '{userbase}',
             },
         'posix_user': {
-            'stdlib': '{userbase}/{platlibdir}/python{py_version_short}',
-            'platstdlib': '{userbase}/{platlibdir}/python{py_version_short}',
-            'purelib': '{userbase}/lib/python{py_version_short}/site-packages',
-            'platlib': '{userbase}/lib/python{py_version_short}/site-packages',
-            'include': '{userbase}/include/python{py_version_short}',
+            'stdlib': '{userbase}/{platlibdir}/python{py_version_short_plat}',
+            'platstdlib': '{userbase}/{platlibdir}/python{py_version_short_plat}',
+            'purelib': '{userbase}/lib/python{py_version_short_plat}/site-packages',
+            'platlib': '{userbase}/lib/python{py_version_short_plat}/site-packages',
+            'include': '{userbase}/include/python{py_version_short_plat}',
             'scripts': '{userbase}/bin',
             'data': '{userbase}',
             },
@@ -287,7 +293,7 @@ def _expand_vars(scheme, vars):
 
 
 def _get_preferred_schemes():
-    if os.name == 'nt':
+    if os.name == 'nt' and not _POSIX_BUILD:
         return {
             'prefix': 'nt',
             'home': 'posix_home',
@@ -445,6 +451,14 @@ def _parse_makefile(filename, vars=None, keep_unresolved=True):
         if isinstance(v, str):
             done[k] = v.strip()
 
+    # any keys that have one with the same name suffixed with _b2h
+    # need to be replaced with the value of the _b2h key.
+    # This converts from MSYS*/Cygwin paths to Windows paths.
+    for k, v in dict(done).items():
+        if isinstance(k, str):
+            if k.endswith("_b2h"):
+                done[k[:-4]]=v
+ 
     # save the results in the global dictionary
     vars.update(done)
     return vars
@@ -524,11 +538,30 @@ def _generate_posix_vars():
     os.makedirs(pybuilddir, exist_ok=True)
     destfile = os.path.join(pybuilddir, name + '.py')
 
+    replacement = """
+        keys_to_replace = [
+            'BINDIR', 'BINLIBDEST', 'CONFINCLUDEDIR',
+            'CONFINCLUDEPY', 'DESTDIRS', 'DESTLIB', 'DESTSHARED',
+            'INCLDIRSTOMAKE', 'INCLUDEDIR', 'INCLUDEPY',
+            'LIBDEST', 'LIBDIR', 'LIBPC', 'LIBPL', 'MACHDESTLIB',
+            'MANDIR', 'SCRIPTDIR', 'datarootdir', 'exec_prefix',
+            'TZPATH',
+        ]
+
+        prefix = build_time_vars['BINDIR'][:-4]
+
+        for key in keys_to_replace:
+            value = build_time_vars[key]
+            build_time_vars[key] = value.replace(prefix, sys.base_prefix)
+    """
+
     with open(destfile, 'w', encoding='utf8') as f:
+        f.write('import sys\n')
         f.write('# system configuration generated and used by'
                 ' the sysconfig module\n')
         f.write('build_time_vars = ')
         pprint.pprint(vars, stream=f)
+        f.write('\n%s' % textwrap.dedent(replacement))
 
     # Create file used for sys.path fixup -- see Modules/getpath.c
     with open('pybuilddir.txt', 'w', encoding='utf8') as f:
@@ -556,7 +589,7 @@ def _init_non_posix(vars):
     except IndexError:
         pass
     vars['EXE'] = '.exe'
-    vars['VERSION'] = _PY_VERSION_SHORT_NO_DOT
+    vars['VERSION'] = _PY_VERSION_SHORT
     vars['BINDIR'] = os.path.dirname(_safe_realpath(sys.executable))
     vars['TZPATH'] = ''
 
@@ -602,7 +635,7 @@ def parse_config_h(fp, vars=None):
 def get_config_h_filename():
     """Return the path of pyconfig.h."""
     if _PYTHON_BUILD:
-        if os.name == "nt":
+        if os.name == "nt" and not _POSIX_BUILD:
             inc_dir = os.path.join(_PROJECT_BASE, "PC")
         else:
             inc_dir = _PROJECT_BASE
@@ -669,11 +702,15 @@ def _init_config_vars():
         _CONFIG_VARS['py_version_nodot_plat'] = sys.winver.replace('.', '')
     except AttributeError:
         _CONFIG_VARS['py_version_nodot_plat'] = ''
+    if os.name == 'nt' and _POSIX_BUILD:
+        _CONFIG_VARS['py_version_short_plat'] = f'{_PY_VERSION_SHORT}-{get_platform()}'
+    else:
+        _CONFIG_VARS['py_version_short_plat'] = _PY_VERSION_SHORT
 
-    if os.name == 'nt':
+    if os.name == 'nt' and not _POSIX_BUILD:
         _init_non_posix(_CONFIG_VARS)
         _CONFIG_VARS['VPATH'] = sys._vpath
-    if os.name == 'posix':
+    if _POSIX_BUILD:
         _init_posix(_CONFIG_VARS)
     if _HAS_USER_BASE:
         # Setting 'userbase' is done below the call to the
@@ -683,7 +720,7 @@ def _init_config_vars():
 
     # Always convert srcdir to an absolute path
     srcdir = _CONFIG_VARS.get('srcdir', _PROJECT_BASE)
-    if os.name == 'posix':
+    if _POSIX_BUILD:
         if _PYTHON_BUILD:
             # If srcdir is a relative path (typically '.' or '..')
             # then it should be interpreted relative to the directory
@@ -756,7 +793,7 @@ def get_config_var(name):
     """
     return get_config_vars().get(name)
 
-
+# make sure to change site._get_platform() while changing this function
 def get_platform():
     """Return a string that identifies the current platform.
 
@@ -780,6 +817,28 @@ def get_platform():
 
     """
     if os.name == 'nt':
+        if 'gcc' in sys.version.lower():
+            platform = 'mingw'
+            if 'amd64' in sys.version.lower():
+                platform += '_x86_64'
+            elif 'arm64' in sys.version.lower():
+                platform += '_aarch64'
+            elif 'arm' in sys.version.lower():
+                platform += '_armv7'
+            else:
+                platform += '_i686'
+
+            if 'ucrt' in sys.version.lower():
+                platform += '_ucrt'
+            else:
+                platform += "_msvcrt"
+
+            if 'clang' in sys.version.lower():
+                platform += "_llvm"
+            else:
+                platform += "_gnu"
+            
+            return platform
         if 'amd64' in sys.version.lower():
             return 'win-amd64'
         if '(arm)' in sys.version.lower():
diff --git a/Lib/test/__main__.py b/Lib/test/__main__.py
index 82b50ad2c6e777..25bac39e24af20 100644
--- a/Lib/test/__main__.py
+++ b/Lib/test/__main__.py
@@ -1,2 +1,10 @@
+import os
+import sys
+
 from test.libregrtest.main import main
+
+if sys.platform == "win32":
+    # Enable DLL loading from PATH.
+    os.environ["PYTHONLEGACYWINDOWSDLLLOADING"] = "1"
+
 main(_add_python_opts=True)
diff --git a/Lib/test/test_bytes.py b/Lib/test/test_bytes.py
index b27d43695eef77..f18d38c6dc0e02 100644
--- a/Lib/test/test_bytes.py
+++ b/Lib/test/test_bytes.py
@@ -1168,7 +1168,7 @@ def test_from_format(self):
 
         if os.name == 'nt':
             # Windows (MSCRT)
-            ptr_format = '0x%0{}X'.format(2 * sizeof_ptr)
+            ptr_format = '0x%0{}x'.format(2 * sizeof_ptr)
             def ptr_formatter(ptr):
                 return (ptr_format % ptr)
         else:
diff --git a/Lib/test/test_getpath.py b/Lib/test/test_getpath.py
index 3b613a569b981a..f63e4204a78a2e 100644
--- a/Lib/test/test_getpath.py
+++ b/Lib/test/test_getpath.py
@@ -837,6 +837,7 @@ def test_symlink_buildpath_macos(self):
     ENV_PYTHONHOME="",
     ENV_PYTHONEXECUTABLE="",
     ENV___PYVENV_LAUNCHER__="",
+    ENV_MSYSTEM="",
     argv0="",
     py_setpath="",
     real_executable="",
@@ -876,6 +877,7 @@ def __init__(self, *a, argv0=None, config=None, **kw):
         self.update(DEFAULT_NAMESPACE)
         self["config"] = DEFAULT_CONFIG.copy()
         self["os_name"] = "nt"
+        self["is_mingw"] = 0
         self["PLATLIBDIR"] = "DLLs"
         self["PYWINVER"] = "9.8-XY"
         self["VPATH"] = r"..\.."
@@ -911,6 +913,9 @@ def __missing__(self, key):
         except AttributeError:
             raise KeyError(key) from None
 
+    def normpath(self, path):
+        return ntpath.normpath(path)
+
     def abspath(self, path):
         if self.isabs(path):
             return path
@@ -1052,6 +1057,7 @@ def __init__(self, *a, argv0=None, config=None, **kw):
         self.update(DEFAULT_NAMESPACE)
         self["config"] = DEFAULT_CONFIG.copy()
         self["os_name"] = "posix"
+        self["is_mingw"] = 0
         self["PLATLIBDIR"] = "lib"
         self["WITH_NEXT_FRAMEWORK"] = 0
         super().__init__(*a, **kw)
@@ -1088,6 +1094,9 @@ def __missing__(self, key):
         except AttributeError:
             raise KeyError(key) from None
 
+    def normpath(self, path):
+        return path
+
     def abspath(self, path):
         if self.isabs(path):
             return path
diff --git a/Lib/test/test_importlib/test_windows.py b/Lib/test/test_importlib/test_windows.py
index 40b8aa1787fe08..0b1254c2d75896 100644
--- a/Lib/test/test_importlib/test_windows.py
+++ b/Lib/test/test_importlib/test_windows.py
@@ -24,6 +24,29 @@ def get_platform():
             'x64' : 'win-amd64',
             'arm' : 'win-arm32',
         }
+    if os.name == 'nt':
+        if "gcc" in sys.version.lower():
+            platform = "mingw"
+            if "amd64" in sys.version.lower():
+                platform += "_x86_64"
+            elif "arm64" in sys.version.lower():
+                platform += "_aarch64"
+            elif "arm" in sys.version.lower():
+                platform += "_armv7"
+            else:
+                platform += "_i686"
+
+            if "ucrt" in sys.version.lower():
+                platform += "_ucrt"
+            else:
+                platform += "_msvcrt"
+
+            if "clang" in sys.version.lower():
+                platform += "_llvm"
+            else:
+                platform += "_gnu"
+
+            return platform
     if ('VSCMD_ARG_TGT_ARCH' in os.environ and
         os.environ['VSCMD_ARG_TGT_ARCH'] in TARGET_TO_PLAT):
         return TARGET_TO_PLAT[os.environ['VSCMD_ARG_TGT_ARCH']]
diff --git a/Lib/test/test_sysconfig.py b/Lib/test/test_sysconfig.py
index 67647e1b787ce7..a883037c1199d2 100644
--- a/Lib/test/test_sysconfig.py
+++ b/Lib/test/test_sysconfig.py
@@ -19,7 +19,7 @@
 from sysconfig import (get_paths, get_platform, get_config_vars,
                        get_path, get_path_names, _INSTALL_SCHEMES,
                        get_default_scheme, get_scheme_names, get_config_var,
-                       _expand_vars, _get_preferred_schemes, _main)
+                       _expand_vars, _get_preferred_schemes, _main, _POSIX_BUILD)
 import _osx_support
 
 
@@ -197,7 +197,7 @@ def test_nt_venv_scheme(self):
         self.assertEqual(libpath, sysconfig.get_path('purelib', scheme='nt_venv', vars=vars))
 
     def test_venv_scheme(self):
-        if sys.platform == 'win32':
+        if not _POSIX_BUILD and sys.platform == 'win32':
             self.assertEqual(
                 sysconfig.get_path('scripts', scheme='venv'),
                 sysconfig.get_path('scripts', scheme='nt_venv')
@@ -388,6 +388,10 @@ def test_user_similar(self):
             if HAS_USER_BASE:
                 user_path = get_path(name, 'posix_user')
                 expected = os.path.normpath(global_path.replace(base, user, 1))
+                if os.name == 'nt' and _POSIX_BUILD:
+                    expected = expected.replace(
+                        f'python{sysconfig.get_python_version()}',
+                        f'python{sysconfig.get_python_version()}-{get_platform()}')
                 # bpo-44860: platlib of posix_user doesn't use sys.platlibdir,
                 # whereas posix_prefix does.
                 if name == 'platlib':
diff --git a/Lib/test/test_tools/test_makefile.py b/Lib/test/test_tools/test_makefile.py
index f1f0cd87ba7496..596e50dfbe2842 100644
--- a/Lib/test/test_tools/test_makefile.py
+++ b/Lib/test/test_tools/test_makefile.py
@@ -33,11 +33,12 @@ def list_test_dirs(self):
                     if '\t' not in line:
                         break
                     result.append(line.replace('\\', '').strip())
+        result = [os.path.normpath(d) for d in result if d]
         return result
 
     def test_makefile_test_folders(self):
         test_dirs = self.list_test_dirs()
-        idle_test = 'idlelib/idle_test'
+        idle_test = os.path.join('idlelib', 'idle_test')
         self.assertIn(idle_test, test_dirs)
 
         used = [idle_test]
diff --git a/Lib/test/test_wmi.py b/Lib/test/test_wmi.py
index 111f990656ced5..3dc452e79fe388 100644
--- a/Lib/test/test_wmi.py
+++ b/Lib/test/test_wmi.py
@@ -8,7 +8,7 @@
 
 
 # Do this first so test will be skipped if module doesn't exist
-_wmi = import_helper.import_module('_wmi', required_on=['win'])
+_wmi = import_helper.import_module('_wmi')
 
 
 def wmi_exec_query(query):
diff --git a/Lib/venv/__init__.py b/Lib/venv/__init__.py
index aeb522c3199ca2..7266f83fef2434 100644
--- a/Lib/venv/__init__.py
+++ b/Lib/venv/__init__.py
@@ -13,6 +13,7 @@
 import types
 import shlex
 
+from sysconfig import _POSIX_BUILD
 
 CORE_VENV_DEPS = ('pip',)
 logger = logging.getLogger(__name__)
@@ -330,7 +331,7 @@ def setup_python(self, context):
                     if not os.path.islink(path):
                         os.chmod(path, 0o755)
         else:
-            if self.symlinks:
+            if self.symlinks and not _POSIX_BUILD:
                 # For symlinking, we need a complete copy of the root directory
                 # If symlinks fail, you'll get unnecessary copies of files, but
                 # we assume that if you've opted into symlinks on Windows then
@@ -354,6 +355,12 @@ def setup_python(self, context):
                 if os.path.lexists(src):
                     copier(src, os.path.join(binpath, suffix))
 
+            if _POSIX_BUILD:
+                # copy from python/pythonw so the venvlauncher magic in symlink_or_copy triggers
+                copier(os.path.join(dirname, 'python.exe'), os.path.join(binpath, 'python3.exe'))
+                copier(os.path.join(dirname, 'python.exe'), os.path.join(binpath, 'python%d.%d.exe' % sys.version_info[:2]))
+                copier(os.path.join(dirname, 'pythonw.exe'), os.path.join(binpath, 'python3w.exe'))
+
             if sysconfig.is_python_build():
                 # copy init.tcl
                 for root, dirs, files in os.walk(context.python_dir):
@@ -378,6 +385,7 @@ def _call_new_python(self, context, *py_args, **kwargs):
         env['VIRTUAL_ENV'] = context.env_dir
         env.pop('PYTHONHOME', None)
         env.pop('PYTHONPATH', None)
+        env.pop("MSYSTEM", None)
         kwargs['cwd'] = context.env_dir
         kwargs['executable'] = context.env_exec_cmd
         subprocess.check_output(args, **kwargs)
diff --git a/Makefile.pre.in b/Makefile.pre.in
index 7ca3dc62c01555..db789988936dc1 100644
--- a/Makefile.pre.in
+++ b/Makefile.pre.in
@@ -38,6 +38,7 @@ CC=		@CC@
 CXX=		@CXX@
 LINKCC=		@LINKCC@
 AR=		@AR@
+WINDRES=	@WINDRES@
 READELF=	@READELF@
 SOABI=		@SOABI@
 LDVERSION=	@LDVERSION@
@@ -124,6 +125,7 @@ PY_CORE_CFLAGS=	$(PY_STDMODULE_CFLAGS) -DPy_BUILD_CORE
 PY_CORE_LDFLAGS=$(PY_LDFLAGS) $(PY_LDFLAGS_NODIST)
 # Strict or non-strict aliasing flags used to compile dtoa.c, see above
 CFLAGS_ALIASING=@CFLAGS_ALIASING@
+RCFLAGS=@RCFLAGS@
 
 
 # Machine-dependent subdirectories
@@ -142,6 +144,12 @@ exec_prefix=	@exec_prefix@
 # Install prefix for data files
 datarootdir=    @datarootdir@
 
+# Locations needed for semi-native fixup of sysconfig.
+srcdir_b2h=		@srcdir_b2h@
+abs_srcdir_b2h=		@abs_srcdir_b2h@
+abs_builddir_b2h=	@abs_builddir_b2h@
+prefix_b2h=		@prefix_b2h@
+
 # Expanded directories
 BINDIR=		@bindir@
 LIBDIR=		@libdir@
@@ -161,10 +169,12 @@ BINLIBDEST=	@BINLIBDEST@
 LIBDEST=	$(SCRIPTDIR)/python$(VERSION)
 INCLUDEPY=	$(INCLUDEDIR)/python$(LDVERSION)
 CONFINCLUDEPY=	$(CONFINCLUDEDIR)/python$(LDVERSION)
+VENVLAUNCHERDIR=	$(BINLIBDEST)/venv/scripts/nt
 
 # Symbols used for using shared libraries
 SHLIB_SUFFIX=	@SHLIB_SUFFIX@
 EXT_SUFFIX=	@EXT_SUFFIX@
+PYD_PLATFORM_TAG = @PYD_PLATFORM_TAG@
 LDSHARED=	@LDSHARED@ $(PY_LDFLAGS)
 BLDSHARED=	@BLDSHARED@ $(PY_CORE_LDFLAGS)
 LDCXXSHARED=	@LDCXXSHARED@ $(PY_LDFLAGS)
@@ -263,6 +273,8 @@ LIBRARY_DEPS=	@LIBRARY_DEPS@
 LINK_PYTHON_DEPS=@LINK_PYTHON_DEPS@
 PY_ENABLE_SHARED=	@PY_ENABLE_SHARED@
 STATIC_LIBPYTHON=	@STATIC_LIBPYTHON@
+ABI3DLLLIBRARY= libpython3.dll
+ABI3LDLIBRARY=  libpython3.dll.a
 
 
 LIBS=		@LIBS@
@@ -279,6 +291,9 @@ LIBOBJS=	@LIBOBJS@
 
 PYTHON=		python$(EXE)
 BUILDPYTHON=	python$(BUILDEXE)
+BUILDPYTHONW=	pythonw$(BUILDEXE)
+BUILDVENVLAUNCHER=	venvlauncher$(BUILDEXE)
+BUILDVENVWLAUNCHER=	venvwlauncher$(BUILDEXE)
 
 HOSTRUNNER= @HOSTRUNNER@
 
@@ -336,6 +351,10 @@ IO_OBJS=	\
 		Modules/_io/bytesio.o \
 		Modules/_io/stringio.o
 
+##########################################################################
+
+NCURSESW_INCLUDEDIR=	@NCURSESW_INCLUDEDIR@
+
 ##########################################################################
 # Parser
 
@@ -383,7 +402,7 @@ PYTHON_OBJS=	\
 		Python/errors.o \
 		Python/flowgraph.o \
 		Python/frame.o \
-		Python/frozenmain.o \
+		@PYTHON_OBJS_FROZENMAIN@ \
 		Python/future.o \
 		Python/getargs.o \
 		Python/getcompiler.o \
@@ -399,6 +418,7 @@ PYTHON_OBJS=	\
 		Python/instrumentation.o \
 		Python/intrinsics.o \
 		Python/legacy_tracing.o \
+		Python/iscygpty.o \
 		Python/marshal.o \
 		Python/modsupport.o \
 		Python/mysnprintf.o \
@@ -614,8 +634,8 @@ all:		@DEF_MAKE_ALL_RULE@
 .PHONY: all
 
 .PHONY: build_all
-build_all:	check-clean-src $(BUILDPYTHON) platform sharedmods \
-		gdbhooks Programs/_testembed scripts checksharedmods rundsymutil
+build_all:	check-clean-src $(BUILDPYTHON) $(BUILDPYTHONW) $(BUILDVENVLAUNCHER) $(BUILDVENVWLAUNCHER) platform sharedmods \
+		gdbhooks Programs/_testembed scripts checksharedmods rundsymutil $(ABI3DLLLIBRARY) $(ABI3LDLIBRARY)
 
 .PHONY: build_wasm
 build_wasm: check-clean-src $(BUILDPYTHON) platform sharedmods \
@@ -781,9 +801,36 @@ coverage-report: regen-token regen-frozen
 clinic: check-clean-src $(srcdir)/Modules/_blake2/blake2s_impl.c
 	$(PYTHON_FOR_REGEN) $(srcdir)/Tools/clinic/clinic.py --make --srcdir $(srcdir)
 
+python_exe.o: $(srcdir)/PC/python_exe.rc
+	$(WINDRES) $(RCFLAGS) -I$(srcdir)/Include -I$(srcdir)/PC -I. $(srcdir)/PC/python_exe.rc $@
+
+pythonw_exe.o: $(srcdir)/PC/pythonw_exe.rc
+	$(WINDRES) $(RCFLAGS) -I$(srcdir)/Include -I$(srcdir)/PC -I. $(srcdir)/PC/pythonw_exe.rc $@
+
+python_nt.o: $(srcdir)/PC/python_nt.rc
+	$(WINDRES) $(RCFLAGS) -DORIGINAL_FILENAME=\\\"$(DLLLIBRARY)\\\" -I$(srcdir)/Include -I$(srcdir)/PC -I. $(srcdir)/PC/python_nt.rc $@
+
+python3dll_nt.o: $(srcdir)/PC/python_nt.rc
+	$(WINDRES) $(RCFLAGS) -DORIGINAL_FILENAME=\\\"$(ABI3DLLLIBRARY)\\\" -I$(srcdir)/Include -I$(srcdir)/PC -I. $(srcdir)/PC/python_nt.rc $@
+
+venvlauncher.o: $(srcdir)/PC/pylauncher.rc
+	$(WINDRES) $(RCFLAGS) -DPY_ICON -I$(srcdir)/Include -I$(srcdir)/PC -I. $(srcdir)/PC/pylauncher.rc $@
+
+venvwlauncher.o: $(srcdir)/PC/pylauncher.rc
+	$(WINDRES) $(RCFLAGS) -DPYW_ICON -I$(srcdir)/Include -I$(srcdir)/PC -I. $(srcdir)/PC/pylauncher.rc $@
+
+$(BUILDPYTHONW): Programs/python.o $(LIBRARY) $(LDLIBRARY) $(PY3LIBRARY) pythonw_exe.o
+	$(LINKCC) $(PY_CORE_LDFLAGS) $(LINKFORSHARED) -municode -mwindows -o $@ Programs/python.o $(BLDLIBRARY) $(LIBS) $(MODLIBS) $(SYSLIBS) pythonw_exe.o
+
 # Build the interpreter
-$(BUILDPYTHON):	Programs/python.o $(LINK_PYTHON_DEPS)
-	$(LINKCC) $(PY_CORE_LDFLAGS) $(LINKFORSHARED) -o $@ Programs/python.o $(LINK_PYTHON_OBJS) $(LIBS) $(MODLIBS) $(SYSLIBS)
+$(BUILDPYTHON):	Programs/python.o $(LINK_PYTHON_DEPS) python_exe.o
+	$(LINKCC) $(PY_CORE_LDFLAGS) $(LINKFORSHARED) -municode -o $@ Programs/python.o $(LINK_PYTHON_OBJS) $(LIBS) $(MODLIBS) $(SYSLIBS) python_exe.o
+
+$(BUILDVENVLAUNCHER): $(BUILDPYTHON) venvlauncher.o  $(srcdir)/PC/launcher.c
+	$(LINKCC) -D_CONSOLE -DVENV_REDIRECT -DPYTHON_EXECUTABLE_WITH_VERSION="L\"python$(LDVERSION)$(EXE)\"" $(PY_STDMODULE_CFLAGS) -municode -static -static-libgcc -static-libstdc++ venvlauncher.o $(srcdir)/PC/launcher.c -o $@ -lversion
+
+$(BUILDVENVWLAUNCHER): $(BUILDPYTHONW) venvwlauncher.o  $(srcdir)/PC/launcher.c
+	$(LINKCC) -D_WINDOWS -DVENV_REDIRECT -DPYTHON_EXECUTABLE_WITH_VERSION="L\"pythonw$(LDVERSION)$(EXE)\"" $(PY_STDMODULE_CFLAGS) -mwindows -municode -static -static-libgcc -static-libstdc++ venvwlauncher.o $(srcdir)/PC/launcher.c -o $@ -lversion
 
 platform: $(PYTHON_FOR_BUILD_DEPS) pybuilddir.txt
 	$(RUNSHARED) $(PYTHON_FOR_BUILD) -c 'import sys ; from sysconfig import get_platform ; print("%s-%d.%d" % (get_platform(), *sys.version_info[:2]))' >platform
@@ -872,13 +919,17 @@ $(PYTHONFRAMEWORKDIR)/Versions/$(VERSION)/$(PYTHONFRAMEWORK): \
 
 # This rule builds the Cygwin Python DLL and import library if configured
 # for a shared core library; otherwise, this rule is a noop.
-$(DLLLIBRARY) libpython$(LDVERSION).dll.a: $(LIBRARY_OBJS)
+$(DLLLIBRARY) libpython$(LDVERSION).dll.a: $(LIBRARY_OBJS) python_nt.o
 	if test -n "$(DLLLIBRARY)"; then \
 		$(LDSHARED) -Wl,--out-implib=$@ -o $(DLLLIBRARY) $^ \
-			$(LIBS) $(MODLIBS) $(SYSLIBS); \
+			$(LIBS) $(LDFLAGS_NODIST) $(MODLIBS) $(SYSLIBS) python_nt.o; \
 	else true; \
 	fi
 
+$(ABI3DLLLIBRARY) $(ABI3LDLIBRARY): python3dll_nt.o $(srcdir)/PC/launcher.c
+	$(LDSHARED) -DPYTHON_DLL_NAME=\"$(DLLLIBRARY)\" $(srcdir)/PC/python3dll.c -Wl,--out-implib=$(ABI3LDLIBRARY) -o $(ABI3DLLLIBRARY) python3dll_nt.o \
+		$(LDFLAGS_NODIST);
+
 # wasm32-emscripten browser build
 # wasm assets directory is relative to current build dir, e.g. "./usr/local".
 # --preload-file turns a relative asset path into an absolute path.
@@ -1072,7 +1123,7 @@ BOOTSTRAP_HEADERS = \
 Programs/_bootstrap_python.o: Programs/_bootstrap_python.c $(BOOTSTRAP_HEADERS) $(PYTHON_HEADERS)
 
 _bootstrap_python: $(LIBRARY_OBJS_OMIT_FROZEN) Programs/_bootstrap_python.o Modules/getpath.o Modules/Setup.local
-	$(LINKCC) $(PY_LDFLAGS_NOLTO) -o $@ $(LIBRARY_OBJS_OMIT_FROZEN) \
+	$(LINKCC) $(PY_LDFLAGS_NOLTO) -o $@ -municode -mwindows $(LIBRARY_OBJS_OMIT_FROZEN) \
 		Programs/_bootstrap_python.o Modules/getpath.o $(LIBS) $(MODLIBS) $(SYSLIBS)
 
 
@@ -1378,9 +1429,15 @@ Python/dynload_hpux.o: $(srcdir)/Python/dynload_hpux.c Makefile
 		-DSHLIB_EXT='"$(EXT_SUFFIX)"' \
 		-o $@ $(srcdir)/Python/dynload_hpux.c
 
+Python/dynload_win.o: $(srcdir)/Python/dynload_win.c Makefile
+	$(CC) -c $(PY_CORE_CFLAGS) \
+		-DPYD_PLATFORM_TAG='"$(PYD_PLATFORM_TAG)"' \
+		-o $@ $(srcdir)/Python/dynload_win.c
+
 Python/sysmodule.o: $(srcdir)/Python/sysmodule.c Makefile $(srcdir)/Include/pydtrace.h
 	$(CC) -c $(PY_CORE_CFLAGS) \
 		-DABIFLAGS='"$(ABIFLAGS)"' \
+		-DVPATH='"$(VPATH)"' \
 		$(MULTIARCH_CPPFLAGS) \
 		-o $@ $(srcdir)/Python/sysmodule.c
 
@@ -1623,6 +1680,7 @@ PYTHON_HEADERS= \
 		$(srcdir)/Include/import.h \
 		$(srcdir)/Include/interpreteridobject.h \
 		$(srcdir)/Include/intrcheck.h \
+		$(srcdir)/Include/iscygpty.h \
 		$(srcdir)/Include/iterobject.h \
 		$(srcdir)/Include/listobject.h \
 		$(srcdir)/Include/longobject.h \
@@ -1954,7 +2012,7 @@ sharedinstall: all
 # This goes into $(exec_prefix)
 .PHONY: altbininstall
 altbininstall: $(BUILDPYTHON) @FRAMEWORKPYTHONW@
-	@for i in $(BINDIR) $(LIBDIR); \
+	@for i in $(BINDIR) $(LIBDIR) $(VENVLAUNCHERDIR); \
 	do \
 		if test ! -d $(DESTDIR)$$i; then \
 			echo "Creating directory $$i"; \
@@ -1964,6 +2022,9 @@ altbininstall: $(BUILDPYTHON) @FRAMEWORKPYTHONW@
 	done
 	if test "$(PYTHONFRAMEWORKDIR)" = "no-framework" ; then \
 		$(INSTALL_PROGRAM) $(BUILDPYTHON) $(DESTDIR)$(BINDIR)/python$(LDVERSION)$(EXE); \
+		$(INSTALL_PROGRAM) $(BUILDPYTHONW) $(DESTDIR)$(BINDIR)/python3w$(EXE); \
+		$(INSTALL_PROGRAM) $(BUILDVENVLAUNCHER) $(DESTDIR)$(VENVLAUNCHERDIR)/python$(EXE); \
+		$(INSTALL_PROGRAM) $(BUILDVENVWLAUNCHER) $(DESTDIR)$(VENVLAUNCHERDIR)/pythonw$(EXE); \
 	else \
 		$(INSTALL_PROGRAM) $(STRIPFLAG) Mac/pythonw $(DESTDIR)$(BINDIR)/python$(LDVERSION)$(EXE); \
 	fi
@@ -1977,6 +2038,7 @@ altbininstall: $(BUILDPYTHON) @FRAMEWORKPYTHONW@
 		if test -f $(LDLIBRARY) && test "$(PYTHONFRAMEWORKDIR)" = "no-framework" ; then \
 			if test -n "$(DLLLIBRARY)" ; then \
 				$(INSTALL_SHARED) $(DLLLIBRARY) $(DESTDIR)$(BINDIR); \
+				$(INSTALL_SHARED) $(ABI3DLLLIBRARY) $(DESTDIR)$(BINDIR); \
 			else \
 				$(INSTALL_SHARED) $(LDLIBRARY) $(DESTDIR)$(LIBDIR)/$(INSTSONAME); \
 				if test $(LDLIBRARY) != $(INSTSONAME); then \
@@ -2109,9 +2171,10 @@ LIBSUBDIRS=	asyncio \
 		tkinter \
 		tomllib \
 		turtledemo \
+		msilib \
 		unittest \
 		urllib \
-		venv venv/scripts venv/scripts/common venv/scripts/posix \
+		venv venv/scripts venv/scripts/common venv/scripts/nt venv/scripts/posix \
 		wsgiref \
 		$(XMLLIBSUBDIRS) \
 		xmlrpc \
@@ -2451,8 +2514,9 @@ libainstall: all scripts
 	@if test "$(STATIC_LIBPYTHON)" = 1; then \
 		if test -d $(LIBRARY); then :; else \
 			if test "$(PYTHONFRAMEWORKDIR)" = no-framework; then \
-				if test "$(SHLIB_SUFFIX)" = .dll; then \
-					$(INSTALL_DATA) $(LDLIBRARY) $(DESTDIR)$(LIBPL) ; \
+				if test "$(SHLIB_SUFFIX)" = .dll -o "$(SHLIB_SUFFIX)" = .pyd; then \
+					$(INSTALL_DATA) $(LDLIBRARY) $(DESTDIR)$(LIBDIR) ; \
+					$(INSTALL_DATA) $(ABI3LDLIBRARY) $(DESTDIR)$(LIBDIR) ; \
 				else \
 					$(INSTALL_DATA) $(LIBRARY) $(DESTDIR)$(LIBPL)/$(LIBRARY) ; \
 				fi; \
@@ -2706,7 +2770,7 @@ clean: clean-retain-profile clean-bolt
 
 .PHONY: clobber
 clobber: clean
-	-rm -f $(BUILDPYTHON) $(LIBRARY) $(LDLIBRARY) $(DLLLIBRARY) \
+	-rm -f $(BUILDPYTHON) $(LIBRARY) $(LDLIBRARY) $(DLLLIBRARY)$(ABI3LDLIBRARY) $(ABI3DLLLIBRARY) \
 		tags TAGS \
 		config.cache config.log pyconfig.h Modules/config.c
 	-rm -rf build platform
diff --git a/Misc/config_mingw b/Misc/config_mingw
new file mode 100644
index 00000000000000..9be43fd3a11407
--- /dev/null
+++ b/Misc/config_mingw
@@ -0,0 +1,15 @@
+# configure defaults for mingw* hosts
+
+# mingw functions to ignore
+ac_cv_func_ftruncate=ignore	# implement it as _chsize
+
+# mingw-w64 functions to ignore
+ac_cv_func_truncate=ignore
+ac_cv_func_alarm=ignore
+
+# files to ignore
+ac_cv_file__dev_ptmx=ignore #NOTE: under MSYS environment device exist
+ac_cv_file__dev_ptc=no
+
+# force detection of winsock2 functionality - require wxp or newer
+ac_cv_func_getpeername=yes
diff --git a/Misc/cross_mingw32 b/Misc/cross_mingw32
new file mode 100644
index 00000000000000..03fde9e6af3ad7
--- /dev/null
+++ b/Misc/cross_mingw32
@@ -0,0 +1,11 @@
+# configure defaults for mingw32 host if cross-build
+
+ac_cv_little_endian_double=yes
+ac_cv_big_endian_double=no
+ac_cv_mixed_endian_double=no
+
+ac_cv_tanh_preserves_zero_sign=yes
+
+ac_cv_wchar_t_signed=no
+
+ac_cv_have_size_t_format=no
diff --git a/Misc/python-config.sh.in b/Misc/python-config.sh.in
index 2602fe24c0402e..195c317ada3825 100644
--- a/Misc/python-config.sh.in
+++ b/Misc/python-config.sh.in
@@ -1,32 +1,44 @@
 #!/bin/sh
 
-# Keep this script in sync with python-config.in
-
 exit_with_usage ()
 {
     echo "Usage: $0 --prefix|--exec-prefix|--includes|--libs|--cflags|--ldflags|--extension-suffix|--help|--abiflags|--configdir|--embed"
-    exit $1
+    exit 1
 }
 
+# Really, python-config.py (and thus .sh) should be called directly, but
+# sometimes software (e.g. GDB) calls python-config.sh as if it were the
+# Python executable, passing python-config.py as the first argument.
+# Work around that oddness by ignoring any .py passed as first arg.
+case "$1" in
+    *.py)
+        shift
+    ;;
+esac
+
 if [ "$1" = "" ] ; then
-    exit_with_usage 1
+    exit_with_usage
 fi
 
 # Returns the actual prefix where this script was installed to.
 installed_prefix ()
 {
-    RESULT=$(dirname $(cd $(dirname "$1") && pwd -P))
-    if which readlink >/dev/null 2>&1 ; then
-        if readlink -f "$RESULT" >/dev/null 2>&1; then
-          RESULT=$(readlink -f "$RESULT")
-        fi
+    local RESULT=$(dirname $(cd $(dirname "$1") && pwd -P))
+    if [ $(which readlink) ] ; then
+        RESULT=$(readlink -f "$RESULT")
+    fi
+    # Since we don't know where the output from this script will end up
+    # we keep all paths in Windows-land since MSYS2 can handle that
+    # while native tools can't handle paths in MSYS2-land.
+    if [ "$OSTYPE" = "cygwin" ] || [ "$OSTYPE" = "msys" ] ; then
+        RESULT=$(cd "$RESULT" && pwd -W)
     fi
     echo $RESULT
 }
 
 prefix_real=$(installed_prefix "$0")
 
-# Use sed to fix paths from their built-to locations to their installed-to
+# Use sed to fix paths from their built-to locations to their installed to
 # locations. Keep prefix & exec_prefix using their original values in case
 # they are referenced in other configure variables, to prevent double
 # substitution, issue #22140.
@@ -41,13 +53,17 @@ LIBM="@LIBM@"
 LIBC="@LIBC@"
 SYSLIBS="$LIBM $LIBC"
 ABIFLAGS="@ABIFLAGS@"
+# Protect against lack of substitution.
+if [ "$ABIFLAGS" = "@""ABIFLAGS""@" ] ; then
+    ABIFLAGS=
+fi
 LIBS="@LIBPYTHON@ @LIBS@ $SYSLIBS"
 LIBS_EMBED="-lpython${VERSION}${ABIFLAGS} @LIBS@ $SYSLIBS"
 BASECFLAGS="@BASECFLAGS@"
-LDLIBRARY="@LDLIBRARY@"
 OPT="@OPT@"
 PY_ENABLE_SHARED="@PY_ENABLE_SHARED@"
 LDVERSION="@LDVERSION@"
+LDLIBRARY="@LDLIBRARY@"
 LIBDEST=${prefix_real}/lib/python${VERSION}
 LIBPL=$(echo "@LIBPL@" | sed "s#$prefix#$prefix_real#")
 SO="@EXT_SUFFIX@"
@@ -61,7 +77,7 @@ for ARG in $*
 do
     case $ARG in
         --help)
-            exit_with_usage 0
+            exit_with_usage
         ;;
         --embed)
             PY_EMBED=1
@@ -69,7 +85,7 @@ do
         --prefix|--exec-prefix|--includes|--libs|--cflags|--ldflags|--extension-suffix|--abiflags|--configdir)
         ;;
         *)
-            exit_with_usage 1
+            exit_with_usage
         ;;
     esac
 done
@@ -80,37 +96,37 @@ fi
 
 for ARG in "$@"
 do
-    case "$ARG" in
+    case $ARG in
         --prefix)
-            echo "$prefix_real"
+            echo -ne "$prefix_real"
         ;;
         --exec-prefix)
-            echo "$exec_prefix_real"
+            echo -ne "$exec_prefix_real "
         ;;
         --includes)
-            echo "$INCDIR $PLATINCDIR"
+            echo -ne "$INCDIR $PLATINCDIR"
         ;;
         --cflags)
-            echo "$INCDIR $PLATINCDIR $BASECFLAGS $CFLAGS $OPT"
+            echo -ne "$INCDIR $PLATINCDIR $BASECFLAGS $CFLAGS $OPT"
         ;;
         --libs)
-            echo "$LIBS"
+            echo -ne "$LIBS"
         ;;
         --ldflags)
             LIBPLUSED=
             if [ "$PY_ENABLE_SHARED" = "0" ] ; then
                 LIBPLUSED="-L$LIBPL"
             fi
-            echo "$LIBPLUSED -L$libdir $LIBS"
+            echo -ne "$LIBPLUSED -L$libdir $LIBS "
         ;;
         --extension-suffix)
-            echo "$SO"
+            echo -ne "$SO "
         ;;
         --abiflags)
-            echo "$ABIFLAGS"
+            echo -ne "$ABIFLAGS "
         ;;
         --configdir)
-            echo "$LIBPL"
+            echo -ne "$LIBPL "
         ;;
 esac
 done
diff --git a/Modules/Setup.bootstrap.in b/Modules/Setup.bootstrap.in
index 8ef0f203a82a8e..271a5b6ddc0266 100644
--- a/Modules/Setup.bootstrap.in
+++ b/Modules/Setup.bootstrap.in
@@ -8,15 +8,15 @@
 # module C APIs are used in core
 atexit atexitmodule.c
 faulthandler faulthandler.c
-posix posixmodule.c
-_signal signalmodule.c
+@INITSYS@ posixmodule.c
+_signal signalmodule.c -lws2_32
 _tracemalloc _tracemalloc.c
 
 # modules used by importlib, deepfreeze, freeze, runpy, and sysconfig
 _codecs _codecsmodule.c
 _collections _collectionsmodule.c
 errno errnomodule.c
-_io _io/_iomodule.c _io/iobase.c _io/fileio.c _io/bytesio.c _io/bufferedio.c _io/textio.c _io/stringio.c
+_io _io/_iomodule.c _io/iobase.c _io/fileio.c _io/bytesio.c _io/bufferedio.c _io/textio.c _io/stringio.c _io/winconsoleio.c
 itertools itertoolsmodule.c
 _sre _sre/sre.c
 _thread _threadmodule.c
@@ -34,3 +34,8 @@ _symtable symtablemodule.c
 
 # for systems without $HOME env, used by site._getuserbase()
 @MODULE_PWD_TRUE@pwd pwdmodule.c
+
+# build-in modules for windows platform:
+@MODULE_WINREG_TRUE@winreg ../PC/winreg.c
+@MODULE_MSVCRT_TRUE@msvcrt -DPy_BUILD_CORE ../PC/msvcrtmodule.c
+@MODULE__WINAPI_TRUE@_winapi _winapi.c
diff --git a/Modules/Setup.stdlib.in b/Modules/Setup.stdlib.in
index 5e587dd3a5a397..b96db5d6d2b1e9 100644
--- a/Modules/Setup.stdlib.in
+++ b/Modules/Setup.stdlib.in
@@ -160,6 +160,13 @@
 # _scproxy needs SystemConfiguration and CoreFoundation framework
 @MODULE__SCPROXY_TRUE@_scproxy _scproxy.c
 
+############################################################################
+# Windows specific modules
+
+@MODULE__OVERLAPPED_TRUE@_overlapped overlapped.c
+@MODULE__MSI_TRUE@_msi ../PC/_msi.c
+@MODULE_WINSOUND_TRUE@winsound ../PC/winsound.c
+
 
 ############################################################################
 # Test modules
@@ -177,6 +184,7 @@
 @MODULE__TESTMULTIPHASE_TRUE@_testmultiphase _testmultiphase.c
 @MODULE__TESTMULTIPHASE_TRUE@_testsinglephase _testsinglephase.c
 @MODULE__CTYPES_TEST_TRUE@_ctypes_test _ctypes/_ctypes_test.c
+@MODULE__TESTCONSOLE_TRUE@_testconsole ../PC/_testconsole.c
 
 # Limited API template modules; must be built as shared modules.
 @MODULE_XXLIMITED_TRUE@xxlimited xxlimited.c
diff --git a/Modules/_ctypes/_ctypes.c b/Modules/_ctypes/_ctypes.c
index d3b496887b5692..c208223b3f14a5 100644
--- a/Modules/_ctypes/_ctypes.c
+++ b/Modules/_ctypes/_ctypes.c
@@ -3416,6 +3416,18 @@ static PPROC FindAddress(void *handle, const char *name, PyObject *type)
     mangled_name = alloca(strlen(name) + 1 + 1 + 1 + 3); /* \0 _ @ %d */
     if (!mangled_name)
         return NULL;
+    /* Issue: for stdcall decorated export functions MSVC compiler adds
+     * underscore, but GCC compiler create them without. This is
+     * visible by example for _ctypes_test.pyd module.
+     * As well functions from system libraries are without underscore.
+     * Solutions:
+     * - If a python module is build with gcc option --add-stdcall-alias
+     * the module will contain XXX as alias for function XXX@ as result
+     * first search in this method will succeed.
+     * - Distutil may use compiler to create def-file, to modify it as
+     * add underscore alias and with new def file to create module.
+     * - Or may be just to search for function without underscore.
+     */
     for (i = 0; i < 32; ++i) {
         sprintf(mangled_name, "_%s@%d", name, i*4);
         Py_BEGIN_ALLOW_THREADS
@@ -3423,6 +3435,13 @@ static PPROC FindAddress(void *handle, const char *name, PyObject *type)
         Py_END_ALLOW_THREADS
         if (address)
             return address;
+        /* search for function without underscore as weel */
+        sprintf(mangled_name, "%s@%d", name, i*4);
+        Py_BEGIN_ALLOW_THREADS
+        address = (PPROC)GetProcAddress(handle, mangled_name);
+        Py_END_ALLOW_THREADS
+        if (address)
+            return address;
     }
     return NULL;
 #endif
diff --git a/Modules/_gdbmmodule.c b/Modules/_gdbmmodule.c
index ffd7b6420894b2..b536cedffce2a4 100644
--- a/Modules/_gdbmmodule.c
+++ b/Modules/_gdbmmodule.c
@@ -18,7 +18,7 @@
 #include <sys/stat.h>
 #include <sys/types.h>
 
-#if defined(WIN32) && !defined(__CYGWIN__)
+#if defined(WIN32) && !defined(__CYGWIN__) && !defined(__MINGW32__)
 #include "gdbmerrno.h"
 extern const char * gdbm_strerror(gdbm_error);
 #endif
diff --git a/Modules/_io/fileio.c b/Modules/_io/fileio.c
index bab68077a2144a..919b8b0429e84b 100644
--- a/Modules/_io/fileio.c
+++ b/Modules/_io/fileio.c
@@ -20,6 +20,7 @@
 #endif
 #include <stddef.h> /* For offsetof */
 #include "_iomodule.h"
+#include "iscygpty.h"
 
 /*
  * Known likely problems:
@@ -1143,7 +1144,7 @@ _io_FileIO_isatty_impl(fileio *self)
         return err_closed();
     Py_BEGIN_ALLOW_THREADS
     _Py_BEGIN_SUPPRESS_IPH
-    res = isatty(self->fd);
+    res = isatty(self->fd) || is_cygpty(self->fd);
     _Py_END_SUPPRESS_IPH
     Py_END_ALLOW_THREADS
     return PyBool_FromLong(res);
diff --git a/Modules/_localemodule.c b/Modules/_localemodule.c
index db8194372dae49..416bd591ea2664 100644
--- a/Modules/_localemodule.c
+++ b/Modules/_localemodule.c
@@ -12,6 +12,13 @@ This software comes with no warranty. Use at your own risk.
 #define PY_SSIZE_T_CLEAN
 #include "Python.h"
 #include "pycore_fileutils.h"
+#ifdef __MINGW32__
+/* The header libintl.h and library libintl may exist on mingw host.
+ * To be compatible with MSVC build we has to undef some defines.
+ */
+#undef HAVE_LIBINTL_H
+#undef HAVE_BIND_TEXTDOMAIN_CODESET
+#endif
 
 #include <stdio.h>
 #include <locale.h>
diff --git a/Modules/_multiprocessing/multiprocessing.c b/Modules/_multiprocessing/multiprocessing.c
index 8f9daa5c3de0cc..eb2cb5f86f2c9b 100644
--- a/Modules/_multiprocessing/multiprocessing.c
+++ b/Modules/_multiprocessing/multiprocessing.c
@@ -180,7 +180,7 @@ static PyMethodDef module_methods[] = {
     _MULTIPROCESSING_RECV_METHODDEF
     _MULTIPROCESSING_SEND_METHODDEF
 #endif
-#if !defined(POSIX_SEMAPHORES_NOT_ENABLED) && !defined(__ANDROID__)
+#if defined(MS_WINDOWS) || (!defined(POSIX_SEMAPHORES_NOT_ENABLED) && !defined(__ANDROID__))
     _MULTIPROCESSING_SEM_UNLINK_METHODDEF
 #endif
     {NULL}
diff --git a/Modules/_multiprocessing/multiprocessing.h b/Modules/_multiprocessing/multiprocessing.h
index dfc2a8e0799a60..dc92a233d374c6 100644
--- a/Modules/_multiprocessing/multiprocessing.h
+++ b/Modules/_multiprocessing/multiprocessing.h
@@ -23,7 +23,10 @@
 #  endif
 #  define SEM_HANDLE HANDLE
 #  define SEM_VALUE_MAX LONG_MAX
-#  define HAVE_MP_SEMAPHORE
+#    define HAVE_MP_SEMAPHORE
+#  if defined(HAVE_SEM_OPEN) && defined(_POSIX_THREADS)
+#    include <semaphore.h>
+#  endif
 #else
 #  include <fcntl.h>                 /* O_CREAT and O_EXCL */
 #  if defined(HAVE_SEM_OPEN) && !defined(POSIX_SEMAPHORES_NOT_ENABLED)
diff --git a/Modules/_winapi.c b/Modules/_winapi.c
index ac3ee113ffda71..abb32f0bd8c718 100644
--- a/Modules/_winapi.c
+++ b/Modules/_winapi.c
@@ -44,7 +44,9 @@
 #endif
 #include "windows.h"
 #include <winioctl.h>
+#if defined(Py_DEBUG)
 #include <crtdbg.h>
+#endif
 #include "winreparse.h"
 
 #if defined(MS_WIN32) && !defined(MS_WIN64)
@@ -1125,7 +1127,7 @@ getattributelist(PyObject *obj, const char *name, AttributeList *attribute_list)
     DWORD err;
     BOOL result;
     PyObject *value;
-    Py_ssize_t handle_list_size;
+    Py_ssize_t handle_list_size = 0;
     DWORD attribute_count = 0;
     SIZE_T attribute_list_size = 0;
 
diff --git a/Modules/getpath.c b/Modules/getpath.c
index 0a3100007511b1..47b89ebcf522ed 100644
--- a/Modules/getpath.c
+++ b/Modules/getpath.c
@@ -54,6 +54,25 @@
 
 /* HELPER FUNCTIONS for getpath.py */
 
+static PyObject *
+getpath_normpath(PyObject *Py_UNUSED(self), PyObject *args)
+{
+    PyObject *r = NULL;
+    PyObject *pathobj;
+    wchar_t *path;
+    if (!PyArg_ParseTuple(args, "U", &pathobj)) {
+        return NULL;
+    }
+    Py_ssize_t len;
+    wchar_t *buffer = PyUnicode_AsWideCharString(pathobj, &len);
+    if (!buffer) {
+        return NULL;
+    }
+    r = PyUnicode_FromWideChar(_Py_normpath(buffer, len), -1);
+    PyMem_Free(buffer);
+    return r;
+}
+
 static PyObject *
 getpath_abspath(PyObject *Py_UNUSED(self), PyObject *args)
 {
@@ -88,6 +107,12 @@ getpath_basename(PyObject *Py_UNUSED(self), PyObject *args)
     }
     Py_ssize_t end = PyUnicode_GET_LENGTH(path);
     Py_ssize_t pos = PyUnicode_FindChar(path, SEP, 0, end, -1);
+#ifdef ALTSEP
+    if (pos < 0) {
+        // try using altsep
+        pos = PyUnicode_FindChar(path, ALTSEP, 0, end, -1);
+    }
+#endif
     if (pos < 0) {
         return Py_NewRef(path);
     }
@@ -104,6 +129,12 @@ getpath_dirname(PyObject *Py_UNUSED(self), PyObject *args)
     }
     Py_ssize_t end = PyUnicode_GET_LENGTH(path);
     Py_ssize_t pos = PyUnicode_FindChar(path, SEP, 0, end, -1);
+#ifdef ALTSEP
+    if (pos < 0) {
+        // try using altsep
+        pos = PyUnicode_FindChar(path, ALTSEP, 0, end, -1);
+    }
+#endif
     if (pos < 0) {
         return PyUnicode_FromStringAndSize(NULL, 0);
     }
@@ -510,6 +541,7 @@ getpath_realpath(PyObject *Py_UNUSED(self) , PyObject *args)
 
 
 static PyMethodDef getpath_methods[] = {
+    {"normpath", getpath_normpath, METH_VARARGS, NULL},
     {"abspath", getpath_abspath, METH_VARARGS, NULL},
     {"basename", getpath_basename, METH_VARARGS, NULL},
     {"dirname", getpath_dirname, METH_VARARGS, NULL},
@@ -881,6 +913,11 @@ _PyConfig_InitPathConfig(PyConfig *config, int compute_path_config)
 #else
         !decode_to_dict(dict, "os_name", "posix") ||
 #endif
+#ifdef __MINGW32__
+        !int_to_dict(dict, "is_mingw", 1) ||
+#else
+        !int_to_dict(dict, "is_mingw", 0) ||
+#endif
 #ifdef WITH_NEXT_FRAMEWORK
         !int_to_dict(dict, "WITH_NEXT_FRAMEWORK", 1) ||
 #else
@@ -907,6 +944,9 @@ _PyConfig_InitPathConfig(PyConfig *config, int compute_path_config)
         !funcs_to_dict(dict, config->pathconfig_warnings) ||
 #ifndef MS_WINDOWS
         PyDict_SetItemString(dict, "winreg", Py_None) < 0 ||
+#endif
+#ifdef __MINGW32__
+        !env_to_dict(dict, "ENV_MSYSTEM", 0) ||
 #endif
         PyDict_SetItemString(dict, "__builtins__", PyEval_GetBuiltins()) < 0
     ) {
diff --git a/Modules/getpath.py b/Modules/getpath.py
index 9913fcba497d30..d143f9776eff31 100644
--- a/Modules/getpath.py
+++ b/Modules/getpath.py
@@ -30,6 +30,7 @@
 
 # ** Values known at compile time **
 # os_name           -- [in] one of 'nt', 'posix', 'darwin'
+# is_mingw          -- [in] True if targeting MinGW
 # PREFIX            -- [in] sysconfig.get_config_var(...)
 # EXEC_PREFIX       -- [in] sysconfig.get_config_var(...)
 # PYTHONPATH        -- [in] sysconfig.get_config_var(...)
@@ -51,6 +52,7 @@
 # ENV_PYTHONHOME          -- [in] getenv(...)
 # ENV_PYTHONEXECUTABLE    -- [in] getenv(...)
 # ENV___PYVENV_LAUNCHER__ -- [in] getenv(...)
+# ENV_MSYSTEM             -- [in] getenv(...)
 
 # ** Values calculated at runtime **
 # config            -- [in/out] dict of the PyConfig structure
@@ -185,8 +187,27 @@
     ZIP_LANDMARK = f'{platlibdir}/python{VERSION_MAJOR}{VERSION_MINOR}.zip'
     DELIM = ':'
     SEP = '/'
+    ALTSEP = None
 
-elif os_name == 'nt':
+elif os_name == 'nt' and is_mingw:
+    BUILDDIR_TXT = 'pybuilddir.txt'
+    BUILD_LANDMARK = 'Modules/Setup.local'
+    DEFAULT_PROGRAM_NAME = f'python{VERSION_MAJOR}'
+    STDLIB_SUBDIR = f'{platlibdir}/python{VERSION_MAJOR}.{VERSION_MINOR}'
+    STDLIB_LANDMARKS = [f'{STDLIB_SUBDIR}/os.py', f'{STDLIB_SUBDIR}/os.pyc']
+    PLATSTDLIB_LANDMARK = f'{platlibdir}/python{VERSION_MAJOR}.{VERSION_MINOR}/lib-dynload'
+    BUILDSTDLIB_LANDMARKS = ['Lib/os.py']
+    VENV_LANDMARK = 'pyvenv.cfg'
+    ZIP_LANDMARK = f'{platlibdir}/python{VERSION_MAJOR}{VERSION_MINOR}.zip'
+    DELIM = ';'
+    if ENV_MSYSTEM:
+        SEP = '/'
+        ALTSEP = '\\'
+    else:
+        SEP = '\\'
+        ALTSEP = '/'
+
+elif os_name == 'nt': # MSVC
     BUILDDIR_TXT = 'pybuilddir.txt'
     BUILD_LANDMARK = f'{VPATH}\\Modules\\Setup.local'
     DEFAULT_PROGRAM_NAME = f'python'
@@ -199,6 +220,7 @@
     WINREG_KEY = f'SOFTWARE\\Python\\PythonCore\\{PYWINVER}\\PythonPath'
     DELIM = ';'
     SEP = '\\'
+    ALTSEP = '/'
 
 
 # ******************************************************************************
@@ -211,6 +233,8 @@ def search_up(prefix, *landmarks, test=isfile):
             return prefix
         prefix = dirname(prefix)
 
+def _normpath(p):
+    return normpath(p) if p is not None else None
 
 # ******************************************************************************
 # READ VARIABLES FROM config
@@ -263,10 +287,10 @@ def search_up(prefix, *landmarks, test=isfile):
     if not executable:
         executable = real_executable
 
-if not executable and SEP in program_name:
+if not executable and (SEP in program_name or 
+                       (ALTSEP and ALTSEP in program_name)):
     # Resolve partial path program_name against current directory
     executable = abspath(program_name)
-
 if not executable:
     # All platforms default to real_executable if known at this
     # stage. POSIX does not set this value.
@@ -497,15 +521,15 @@ def search_up(prefix, *landmarks, test=isfile):
     except (FileNotFoundError, PermissionError):
         if isfile(joinpath(real_executable_dir, BUILD_LANDMARK)):
             build_prefix = joinpath(real_executable_dir, VPATH)
-            if os_name == 'nt':
+            if os_name == 'nt' and not is_mingw:
                 # QUIRK: Windows builds need platstdlib_dir to be the executable
                 # dir. Normally the builddir marker handles this, but in this
                 # case we need to correct manually.
                 platstdlib_dir = real_executable_dir
 
     if build_prefix:
-        if os_name == 'nt':
-            # QUIRK: No searching for more landmarks on Windows
+        if os_name == 'nt' and not is_mingw:
+            # QUIRK: No searching for more landmarks on MSVC
             build_stdlib_prefix = build_prefix
         else:
             build_stdlib_prefix = search_up(build_prefix, *BUILDSTDLIB_LANDMARKS)
@@ -552,6 +576,9 @@ def search_up(prefix, *landmarks, test=isfile):
     # First try to detect prefix by looking alongside our runtime library, if known
     if library and not prefix:
         library_dir = dirname(library)
+        if os_name == 'nt' and is_mingw:
+            # QUIRK: On Windows, mingw Python DLLs are in the bin directory
+            library_dir = joinpath(library_dir, '..')
         if ZIP_LANDMARK:
             if os_name == 'nt':
                 # QUIRK: Windows does not search up for ZIP file
@@ -597,7 +624,7 @@ def search_up(prefix, *landmarks, test=isfile):
 
     # Detect exec_prefix by searching from executable for the platstdlib_dir
     if PLATSTDLIB_LANDMARK and not exec_prefix:
-        if os_name == 'nt':
+        if os_name == 'nt' and (not is_mingw):
             # QUIRK: Windows always assumed these were the same
             # gh-100320: Our PYDs are assumed to be relative to the Lib directory
             # (that is, prefix) rather than the executable (that is, executable_dir)
@@ -607,7 +634,7 @@ def search_up(prefix, *landmarks, test=isfile):
         if not exec_prefix and EXEC_PREFIX:
             exec_prefix = EXEC_PREFIX
         if not exec_prefix or not isdir(joinpath(exec_prefix, PLATSTDLIB_LANDMARK)):
-            if os_name == 'nt':
+            if os_name == 'nt' and (not is_mingw):
                 # QUIRK: If DLLs is missing on Windows, don't warn, just assume
                 # that they're in exec_prefix
                 if not platstdlib_dir:
@@ -645,7 +672,7 @@ def search_up(prefix, *landmarks, test=isfile):
 
 if py_setpath:
     # If Py_SetPath was called then it overrides any existing search path
-    config['module_search_paths'] = py_setpath.split(DELIM)
+    config['module_search_paths'] = [_normpath(p) for p in py_setpath.split(DELIM)]
     config['module_search_paths_set'] = 1
 
 elif not pythonpath_was_set:
@@ -660,7 +687,7 @@ def search_up(prefix, *landmarks, test=isfile):
             pythonpath.append(abspath(p))
 
     # Then add the default zip file
-    if os_name == 'nt':
+    if os_name == 'nt' and (not is_mingw):
         # QUIRK: Windows uses the library directory rather than the prefix
         if library:
             library_dir = dirname(library)
@@ -673,7 +700,7 @@ def search_up(prefix, *landmarks, test=isfile):
     else:
         pythonpath.append(joinpath(prefix, ZIP_LANDMARK))
 
-    if os_name == 'nt' and use_environment and winreg:
+    if (not is_mingw) and os_name == 'nt' and use_environment and winreg:
         # QUIRK: Windows also lists paths in the registry. Paths are stored
         # as the default value of each subkey of
         # {HKCU,HKLM}\Software\Python\PythonCore\{winver}\PythonPath
@@ -714,7 +741,7 @@ def search_up(prefix, *landmarks, test=isfile):
     if not platstdlib_dir and exec_prefix:
         platstdlib_dir = joinpath(exec_prefix, PLATSTDLIB_LANDMARK)
 
-    if os_name == 'nt':
+    if os_name == 'nt' and (not is_mingw):
         # QUIRK: Windows generates paths differently
         if platstdlib_dir:
             pythonpath.append(platstdlib_dir)
@@ -732,7 +759,7 @@ def search_up(prefix, *landmarks, test=isfile):
         if platstdlib_dir:
             pythonpath.append(platstdlib_dir)
 
-    config['module_search_paths'] = pythonpath
+    config['module_search_paths'] = [_normpath(p) for p in pythonpath]
     config['module_search_paths_set'] = 1
 
 
@@ -742,8 +769,8 @@ def search_up(prefix, *landmarks, test=isfile):
 
 # QUIRK: Non-Windows replaces prefix/exec_prefix with defaults when running
 # in build directory. This happens after pythonpath calculation.
-if os_name != 'nt' and build_prefix:
-    prefix = config.get('prefix') or PREFIX
+if (os_name != 'nt' or is_mingw) and build_prefix:
+    prefix = config.get('prefix') or abspath(PREFIX)
     exec_prefix = config.get('exec_prefix') or EXEC_PREFIX or prefix
 
 
@@ -767,23 +794,23 @@ def search_up(prefix, *landmarks, test=isfile):
             warn("unsupported 'import' line in ._pth file")
         else:
             pythonpath.append(joinpath(pth_dir, line))
-    config['module_search_paths'] = pythonpath
+    config['module_search_paths'] = [_normpath(p) for p in pythonpath]
     config['module_search_paths_set'] = 1
 
 # ******************************************************************************
 # UPDATE config FROM CALCULATED VALUES
 # ******************************************************************************
 
-config['program_name'] = program_name
-config['home'] = home
-config['executable'] = executable
-config['base_executable'] = base_executable
-config['prefix'] = prefix
-config['exec_prefix'] = exec_prefix
-config['base_prefix'] = base_prefix or prefix
-config['base_exec_prefix'] = base_exec_prefix or exec_prefix
+config['program_name'] = _normpath(program_name)
+config['home'] = _normpath(home)
+config['executable'] = _normpath(executable)
+config['base_executable'] = _normpath(base_executable)
+config['prefix'] = _normpath(prefix)
+config['exec_prefix'] = _normpath(exec_prefix)
+config['base_prefix'] = _normpath(base_prefix or prefix)
+config['base_exec_prefix'] = _normpath(base_exec_prefix or exec_prefix)
 
-config['platlibdir'] = platlibdir
+config['platlibdir'] = _normpath(platlibdir)
 # test_embed expects empty strings, not None
-config['stdlib_dir'] = stdlib_dir or ''
-config['platstdlib_dir'] = platstdlib_dir or ''
+config['stdlib_dir'] = _normpath(stdlib_dir or '')
+config['platstdlib_dir'] = _normpath(platstdlib_dir or '')
diff --git a/Modules/main.c b/Modules/main.c
index f4e4018212f59e..fbdccddaee955c 100644
--- a/Modules/main.c
+++ b/Modules/main.c
@@ -7,6 +7,7 @@
 #include "pycore_pathconfig.h"    // _PyPathConfig_ComputeSysPath0()
 #include "pycore_pylifecycle.h"   // _Py_PreInitializeFromPyArgv()
 #include "pycore_pystate.h"       // _PyInterpreterState_GET()
+#include "iscygpty.h"
 
 /* Includes for exit_sigint() */
 #include <stdio.h>                // perror()
@@ -92,7 +93,7 @@ static inline int config_run_code(const PyConfig *config)
 static int
 stdin_is_interactive(const PyConfig *config)
 {
-    return (isatty(fileno(stdin)) || config->interactive);
+    return (isatty(fileno(stdin)) || config->interactive || is_cygpty(fileno(stdin)));
 }
 
 
diff --git a/Modules/makesetup b/Modules/makesetup
index f000c9cd67310e..5e2ada098a5452 100755
--- a/Modules/makesetup
+++ b/Modules/makesetup
@@ -88,7 +88,7 @@ NL='\
 '
 
 # Setup to link with extra libraries when making shared extensions.
-# Currently, only Cygwin needs this baggage.
+# Currently, only Cygwin and MINGW needs this baggage.
 case `uname -s` in
 CYGWIN*) if test $libdir = .
 	 then
@@ -97,6 +97,9 @@ CYGWIN*) if test $libdir = .
 	 	ExtraLibDir='$(LIBPL)'
 	 fi
 	 ExtraLibs="-L$ExtraLibDir -lpython\$(LDVERSION)";;
+*)
+	 ExtraLibs='$(BLDLIBRARY)'
+	 ExtraLibDepends='$(LIBRARY_DEPS)';;
 esac
 
 # Main loop
@@ -285,7 +288,7 @@ sed -e 's/[ 	]*#.*//' -e '/^[ 	]*$/d' |
 				BUILT_SHARED="$BUILT_SHARED $mod"
 				;;
 			esac
-			rule="$file: $objs"
+			rule="$file: $objs $ExtraLibDepends"
 			rule="$rule; \$(BLDSHARED) $objs $libs $ExtraLibs -o $file"
 			echo "$rule" >>$rulesf
 		done
diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c
index c21c6f06c729de..53b93d2e424917 100644
--- a/Modules/posixmodule.c
+++ b/Modules/posixmodule.c
@@ -54,6 +54,7 @@
 #ifdef __ANDROID__
 #  undef HAVE_FACCESSAT
 #endif
+#include "iscygpty.h"
 
 #include <stdio.h>                // ctermid()
 #include <stdlib.h>               // system()
@@ -369,6 +370,32 @@ corresponding Unix manual entries for more information on calls.");
 #  define HAVE_PIPE       1
 #  define HAVE_FSYNC      1
 #  define fsync _commit
+#elif defined(__MINGW32__)	/* GCC for windows hosts */
+/* getlogin is detected by configure on mingw-w64 */
+#  undef HAVE_GETLOGIN
+/* opendir is detected by configure on mingw-w64, and for some reason
+things don't work as expected. For example, os.listdir always returns
+the cwd's directory listing instead of the one specified. By 
+un-defining, this, os.listdir will use the one which uses native
+windows API. */
+#  undef HAVE_OPENDIR
+/*#    define HAVE_GETCWD     1 - detected by configure*/
+#  define HAVE_GETPPID    1
+#  define HAVE_GETLOGIN   1
+#  define HAVE_SPAWNV     1
+#  define HAVE_WSPAWNV    1
+#  define HAVE_WEXECV     1
+/*#    define HAVE_EXECV	     1 - detected by configure*/
+#  define HAVE_PIPE	     1
+#  define HAVE_POPEN	     1
+#  define HAVE_SYSTEM	   1
+#  define HAVE_CWAIT      1
+#  define HAVE_FSYNC      1
+#  define fsync _commit
+#  include <winioctl.h>
+#  ifndef _MAX_ENV
+#    define _MAX_ENV	32767
+#  endif
 #endif  /* ! __WATCOMC__ || __QNX__ */
 
 /*[clinic input]
@@ -446,7 +473,7 @@ extern char        *ctermid_r(char *);
 #  endif
 #endif
 
-#ifdef _MSC_VER
+#ifdef MS_WINDOWS
 #  ifdef HAVE_DIRECT_H
 #    include <direct.h>
 #  endif
@@ -457,7 +484,7 @@ extern char        *ctermid_r(char *);
 #    include <process.h>
 #  endif
 #  include <malloc.h>
-#endif /* _MSC_VER */
+#endif /* MS_WINDOWS */
 
 #ifndef MAXPATHLEN
 #  if defined(PATH_MAX) && PATH_MAX > 1024
@@ -1594,9 +1621,9 @@ _Py_Sigset_Converter(PyObject *obj, void *addr)
 ** man environ(7).
 */
 #include <crt_externs.h>
-#elif !defined(_MSC_VER) && (!defined(__WATCOMC__) || defined(__QNX__) || defined(__VXWORKS__))
+#elif !defined(MS_WINDOWS) && (!defined(__WATCOMC__) || defined(__QNX__) || defined(__VXWORKS__))
 extern char **environ;
-#endif /* !_MSC_VER */
+#endif /* !MS_WINDOWS */
 
 static PyObject *
 convertenviron(void)
@@ -3986,6 +4013,7 @@ posix_getcwd(int use_bytes)
         return NULL;
     }
 
+    Py_NormalizeSepsW(wbuf2);
     PyObject *resobj = PyUnicode_FromWideChar(wbuf2, len);
     if (wbuf2 != wbuf) {
         PyMem_RawFree(wbuf2);
@@ -4872,6 +4900,7 @@ os__getfinalpathname_impl(PyObject *module, path_t *path)
         target_path = tmp;
     }
 
+    Py_NormalizeSepsW(target_path);
     result = PyUnicode_FromWideChar(target_path, result_length);
     if (result && PyBytes_Check(path->object)) {
         Py_SETREF(result, PyUnicode_EncodeFSDefault(result));
@@ -6257,7 +6286,7 @@ os_utime_impl(PyObject *module, path_t *path, PyObject *times, PyObject *ns,
 /*[clinic end generated code: output=cfcac69d027b82cf input=2fbd62a2f228f8f4]*/
 {
 #ifdef MS_WINDOWS
-    HANDLE hFile;
+    HANDLE hFile = 0;
     FILETIME atime, mtime;
 #else
     int result;
@@ -11213,7 +11242,7 @@ os_isatty_impl(PyObject *module, int fd)
     int return_value;
     Py_BEGIN_ALLOW_THREADS
     _Py_BEGIN_SUPPRESS_IPH
-    return_value = isatty(fd);
+    return_value = isatty(fd) || is_cygpty(fd);
     _Py_END_SUPPRESS_IPH
     Py_END_ALLOW_THREADS
     return return_value;
diff --git a/Modules/selectmodule.c b/Modules/selectmodule.c
index 50788e5344c152..89396f31d0daf3 100644
--- a/Modules/selectmodule.c
+++ b/Modules/selectmodule.c
@@ -169,9 +169,9 @@ seq2set(PyObject *seq, fd_set *set, pylist fd2obj[FD_SETSIZE + 1])
         v = PyObject_AsFileDescriptor( o );
         if (v == -1) goto finally;
 
-#if defined(_MSC_VER)
+#if defined(MS_WIN32)
         max = 0;                             /* not used for Win32 */
-#else  /* !_MSC_VER */
+#else  /* !MS_WIN32 */
         if (!_PyIsSelectable_fd(v)) {
             PyErr_SetString(PyExc_ValueError,
                         "filedescriptor out of range in select()");
@@ -179,7 +179,7 @@ seq2set(PyObject *seq, fd_set *set, pylist fd2obj[FD_SETSIZE + 1])
         }
         if (v > max)
             max = v;
-#endif /* _MSC_VER */
+#endif /* MS_WIN32 */
         FD_SET(v, set);
 
         /* add object and its file descriptor to the list */
diff --git a/Modules/socketmodule.c b/Modules/socketmodule.c
index 27afd73d9704db..f0d84d350b6ea8 100644
--- a/Modules/socketmodule.c
+++ b/Modules/socketmodule.c
@@ -279,9 +279,10 @@ shutdown(how) -- shut down traffic in one or both directions\n\
 # endif
 
 /* Helpers needed for AF_HYPERV */
-# include <Rpc.h>
+# include <rpc.h>
 
 /* Macros based on the IPPROTO enum, see: https://bugs.python.org/issue29515 */
+#ifdef _MSC_VER
 #define IPPROTO_ICMP IPPROTO_ICMP
 #define IPPROTO_IGMP IPPROTO_IGMP
 #define IPPROTO_GGP IPPROTO_GGP
@@ -312,6 +313,7 @@ shutdown(how) -- shut down traffic in one or both directions\n\
 #define IPPROTO_PGM IPPROTO_PGM  // WinSock2 only
 #define IPPROTO_L2TP IPPROTO_L2TP  // WinSock2 only
 #define IPPROTO_SCTP IPPROTO_SCTP  // WinSock2 only
+#endif /* _MSC_VER */
 
 /* Provides the IsWindows7SP1OrGreater() function */
 #include <versionhelpers.h>
@@ -426,6 +428,10 @@ remove_unusable_flags(PyObject *m)
   /* Do not include addrinfo.h for MSVC7 or greater. 'addrinfo' and
    * EAI_* constants are defined in (the already included) ws2tcpip.h.
    */
+#elif defined(__MINGW32__)
+  /* Do not include addrinfo.h as minimum supported version is
+   * _WIN32_WINNT >= WindowsXP(0x0501)
+   */
 #else
 #  include "addrinfo.h"
 #endif
diff --git a/Modules/socketmodule.h b/Modules/socketmodule.h
index f5ca00450ee92a..1e92327d04f145 100644
--- a/Modules/socketmodule.h
+++ b/Modules/socketmodule.h
@@ -68,8 +68,10 @@ struct SOCKADDR_BTH_REDEF {
  */
 # ifdef SIO_GET_MULTICAST_FILTER
 #  include <mstcpip.h> /* for SIO_RCVALL */
+#ifndef __MINGW32__ /* resolve by configure */
 #  define HAVE_ADDRINFO
 #  define HAVE_SOCKADDR_STORAGE
+#endif
 #  define HAVE_GETADDRINFO
 #  define HAVE_GETNAMEINFO
 #  define ENABLE_IPV6
diff --git a/Modules/timemodule.c b/Modules/timemodule.c
index 59078263571f7e..4946cdc2f6563a 100644
--- a/Modules/timemodule.c
+++ b/Modules/timemodule.c
@@ -905,7 +905,7 @@ time_strftime(PyObject *module, PyObject *args)
         return NULL;
     }
 
-#if defined(_MSC_VER) || (defined(__sun) && defined(__SVR4)) || defined(_AIX) || defined(__VXWORKS__)
+#if defined(MS_WINDOWS) || (defined(__sun) && defined(__SVR4)) || defined(_AIX) || defined(__VXWORKS__)
     if (buf.tm_year + 1900 < 1 || 9999 < buf.tm_year + 1900) {
         PyErr_SetString(PyExc_ValueError,
                         "strftime() requires year in [1; 9999]");
diff --git a/Objects/fileobject.c b/Objects/fileobject.c
index e99e155f2b8c98..c74d2af4903a55 100644
--- a/Objects/fileobject.c
+++ b/Objects/fileobject.c
@@ -3,6 +3,7 @@
 #define PY_SSIZE_T_CLEAN
 #include "Python.h"
 #include "pycore_call.h"          // _PyObject_CallNoArgs()
+#include "iscygpty.h"
 #include "pycore_runtime.h"       // _PyRuntime
 
 #if defined(HAVE_GETC_UNLOCKED) && !defined(_Py_MEMORY_SANITIZER)
@@ -382,7 +383,7 @@ stdprinter_isatty(PyStdPrinter_Object *self, PyObject *Py_UNUSED(ignored))
     }
 
     Py_BEGIN_ALLOW_THREADS
-    res = isatty(self->fd);
+    res = isatty(self->fd) || is_cygpty(self->fd);
     Py_END_ALLOW_THREADS
 
     return PyBool_FromLong(res);
diff --git a/PC/_testconsole.c b/PC/_testconsole.c
index 3221b985d01ba0..47fbe6feb33832 100644
--- a/PC/_testconsole.c
+++ b/PC/_testconsole.c
@@ -116,7 +116,7 @@ _testconsole_read_output_impl(PyObject *module, PyObject *file)
     Py_RETURN_NONE;
 }
 
-#include "clinic\_testconsole.c.h"
+#include "clinic/_testconsole.c.h"
 
 PyMethodDef testconsole_methods[] = {
     _TESTCONSOLE_WRITE_INPUT_METHODDEF
diff --git a/PC/launcher.c b/PC/launcher.c
index dc265533740b67..ee7600468f1c8b 100644
--- a/PC/launcher.c
+++ b/PC/launcher.c
@@ -924,7 +924,7 @@ static COMMAND path_command;
 static COMMAND * find_on_path(wchar_t * name)
 {
     wchar_t * pathext;
-    size_t    varsize;
+    size_t    requiredSize;
     wchar_t * context = NULL;
     wchar_t * extension;
     COMMAND * result = NULL;
@@ -941,18 +941,23 @@ static COMMAND * find_on_path(wchar_t * name)
     }
     else {
         /* No extension - search using registered extensions. */
-        rc = _wdupenv_s(&pathext, &varsize, L"PATHEXT");
-        if (rc == 0) {
-            extension = wcstok_s(pathext, L";", &context);
-            while (extension) {
-                len = SearchPathW(NULL, name, extension, MSGSIZE, path_command.value, NULL);
-                if (len) {
-                    result = &path_command;
-                    break;
+        _wgetenv_s(&requiredSize, NULL, 0, L"PATHEXT");
+        if (requiredSize > 0) {
+            pathext = (wchar_t *)malloc(requiredSize * sizeof(wchar_t));
+            /* No extension - search using registered extensions. */
+            rc = _wgetenv_s(&requiredSize, pathext, requiredSize, L"PATHEXT");
+            if (rc == 0) {
+                extension = wcstok_s(pathext, L";", &context);
+                while (extension) {
+                    len = SearchPathW(NULL, name, extension, MSGSIZE, path_command.value, NULL);
+                    if (len) {
+                        result = &path_command;
+                        break;
+                    }
+                    extension = wcstok_s(NULL, L";", &context);
                 }
-                extension = wcstok_s(NULL, L";", &context);
+                free(pathext);
             }
-            free(pathext);
         }
     }
     return result;
@@ -1912,7 +1917,7 @@ process(int argc, wchar_t ** argv)
         if (_wfopen_s(&f, venv_cfg_path, L"r")) {
             error(RC_BAD_VENV_CFG, L"Cannot read '%ls'", venv_cfg_path);
         }
-        cb = fread_s(buffer, sizeof(buffer), sizeof(buffer[0]),
+        cb = fread(buffer, sizeof(buffer[0]),
                      sizeof(buffer) / sizeof(buffer[0]), f);
         fclose(f);
 
@@ -1925,7 +1930,8 @@ process(int argc, wchar_t ** argv)
         if (!cch) {
             error(0, L"Cannot determine memory for home path");
         }
-        cch += (DWORD)wcslen(PYTHON_EXECUTABLE) + 4; /* include sep, null and quotes */
+        cch += (DWORD)max(wcslen(PYTHON_EXECUTABLE_WITH_VERSION),
+                          wcslen(PYTHON_EXECUTABLE)) + 4; /* include sep, null and quotes */
         executable = (wchar_t *)malloc(cch * sizeof(wchar_t));
         if (executable == NULL) {
             error(RC_NO_MEMORY, L"A memory allocation failed");
@@ -1943,13 +1949,22 @@ process(int argc, wchar_t ** argv)
             executable[cch_actual++] = L'\\';
             executable[cch_actual] = L'\0';
         }
-        if (wcscat_s(&executable[1], cch - 1, PYTHON_EXECUTABLE)) {
+        if (wcscat_s(&executable[1], cch - 1, PYTHON_EXECUTABLE_WITH_VERSION)) {
             error(RC_BAD_VENV_CFG, L"Cannot create executable path from '%ls'",
                   venv_cfg_path);
         }
         /* there's no trailing quote, so we only have to skip one character for the test */
+        // Check if the versioned executable (PYTHON_EXECUTABLE_WITH_VERSION) exists first
         if (GetFileAttributesW(&executable[1]) == INVALID_FILE_ATTRIBUTES) {
-            error(RC_NO_PYTHON, L"No Python at '%ls'", executable);
+            // If not found, try PYTHON_EXECUTABLE
+            executable[cch_actual] = L'\0';  // Reset the path
+            if (wcscat_s(&executable[1], cch - 1, PYTHON_EXECUTABLE)) {
+                error(RC_BAD_VENV_CFG, L"Cannot create executable path from '%ls'",
+                      venv_cfg_path);
+            }
+            if (GetFileAttributesW(&executable[1]) == INVALID_FILE_ATTRIBUTES) {
+                error(RC_NO_PYTHON, L"No Python at '%ls'", executable);
+            }
         }
         /* now append the final quote */
         wcscat_s(executable, cch, L"\"");
diff --git a/PC/msvcrtmodule.c b/PC/msvcrtmodule.c
index 53ef26b732f615..10cf78258a8084 100644
--- a/PC/msvcrtmodule.c
+++ b/PC/msvcrtmodule.c
@@ -22,7 +22,9 @@
 #include <io.h>
 #include <conio.h>
 #include <sys/locking.h>
+#ifdef _DEBUG
 #include <crtdbg.h>
+#endif
 #include <windows.h>
 
 #ifdef _MSC_VER
diff --git a/PC/pylauncher.rc b/PC/pylauncher.rc
index 11862643aa6989..84b291722f6633 100644
--- a/PC/pylauncher.rc
+++ b/PC/pylauncher.rc
@@ -12,17 +12,17 @@
 1 RT_MANIFEST "python.manifest"
 
 #if defined(PY_ICON)
-1 ICON DISCARDABLE "icons\python.ico"
+1 ICON DISCARDABLE "icons/python.ico"
 #elif defined(PYW_ICON)
-1 ICON DISCARDABLE "icons\pythonw.ico"
+1 ICON DISCARDABLE "icons/pythonw.ico"
 #else
-1 ICON DISCARDABLE "icons\launcher.ico" 
-2 ICON DISCARDABLE "icons\py.ico" 
-3 ICON DISCARDABLE "icons\pyc.ico" 
-4 ICON DISCARDABLE "icons\pyd.ico" 
-5 ICON DISCARDABLE "icons\python.ico"
-6 ICON DISCARDABLE "icons\pythonw.ico"
-7 ICON DISCARDABLE "icons\setup.ico" 
+1 ICON DISCARDABLE "icons/launcher.ico"
+2 ICON DISCARDABLE "icons/py.ico" 
+3 ICON DISCARDABLE "icons/pyc.ico" 
+4 ICON DISCARDABLE "icons/pyd.ico" 
+5 ICON DISCARDABLE "icons/python.ico"
+6 ICON DISCARDABLE "icons/pythonw.ico"
+7 ICON DISCARDABLE "icons/setup.ico" 
 #endif
 
 1 USAGE "launcher-usage.txt"
@@ -64,4 +64,4 @@ BEGIN
     BEGIN
         VALUE "Translation", 0x0, 1200
     END
-END
\ No newline at end of file
+END
diff --git a/PC/python3dll.c b/PC/python3dll.c
index 505feef4b986c4..ee9380c81437e8 100755
--- a/PC/python3dll.c
+++ b/PC/python3dll.c
@@ -2,6 +2,7 @@
 
 /* Generated by Tools/build/stable_abi.py */
 
+#ifdef _MSC_VER
 #ifdef _M_IX86
 #define DECORATE "_"
 #else
@@ -12,6 +13,13 @@
     __pragma(comment(linker, "/EXPORT:" DECORATE #name "=" PYTHON_DLL_NAME "." #name))
 #define EXPORT_DATA(name) \
     __pragma(comment(linker, "/EXPORT:" DECORATE #name "=" PYTHON_DLL_NAME "." #name ",DATA"))
+#else
+// XXX: Why do we need the .dll extension and no DECORATE compared to the MSVC case?
+#define EXPORT_FUNC(name) \
+    asm(".section .drectve\n\t.ascii \" -export:" #name "=\\\"" PYTHON_DLL_NAME "." #name "\\\" \"");
+#define EXPORT_DATA(name) \
+    asm(".section .drectve\n\t.ascii \" -export:" #name "=\\\"" PYTHON_DLL_NAME "." #name "\\\",DATA \"");
+#endif
 
 EXPORT_FUNC(_Py_BuildValue_SizeT)
 EXPORT_FUNC(_Py_CheckRecursiveCall)
diff --git a/PC/python_exe.rc b/PC/python_exe.rc
index c3d3bff019895e..dde0e5384201fa 100644
--- a/PC/python_exe.rc
+++ b/PC/python_exe.rc
@@ -12,7 +12,7 @@
 // current versions of Windows.
 1 RT_MANIFEST "python.manifest"
 
-1 ICON DISCARDABLE "icons\python.ico" 
+1 ICON DISCARDABLE "icons/python.ico"
 
 
 /////////////////////////////////////////////////////////////////////////////
diff --git a/PC/pythonw_exe.rc b/PC/pythonw_exe.rc
index 38570b74fa3e02..7ce1043298eac4 100644
--- a/PC/pythonw_exe.rc
+++ b/PC/pythonw_exe.rc
@@ -12,7 +12,7 @@
 // current versions of Windows.
 1 RT_MANIFEST "python.manifest"
 
-1 ICON DISCARDABLE "icons\pythonw.ico" 
+1 ICON DISCARDABLE "icons/pythonw.ico"
 
 
 /////////////////////////////////////////////////////////////////////////////
diff --git a/PC/winreg.c b/PC/winreg.c
index e2d5322f458c2a..e8f36c19614e0b 100644
--- a/PC/winreg.c
+++ b/PC/winreg.c
@@ -812,6 +812,7 @@ Reg2Py(BYTE *retDataBuf, DWORD retDataSize, DWORD typ)
         case REG_BINARY:
         /* ALSO handle ALL unknown data types here.  Even if we can't
            support it natively, we should handle the bits. */
+           /* fallthrough */
         default:
             if (retDataSize == 0) {
                 obData = Py_NewRef(Py_None);
diff --git a/Python/bltinmodule.c b/Python/bltinmodule.c
index 2ae28693bee05c..d918964a90e4b1 100644
--- a/Python/bltinmodule.c
+++ b/Python/bltinmodule.c
@@ -1,6 +1,7 @@
 /* Built-in functions */
 
 #include "Python.h"
+#include "iscygpty.h"
 #include <ctype.h>
 #include "pycore_ast.h"           // _PyAST_Validate()
 #include "pycore_call.h"          // _PyObject_CallNoArgs()
@@ -2163,7 +2164,7 @@ builtin_input_impl(PyObject *module, PyObject *prompt)
         if (fd < 0 && PyErr_Occurred()) {
             goto error;
         }
-        tty = fd == fileno(stdin) && isatty(fd);
+        tty = fd == fileno(stdin) && (isatty(fd) || is_cygpty(fd));
     }
     if (tty) {
         tmp = PyObject_CallMethodNoArgs(fout, &_Py_ID(fileno));
@@ -2176,7 +2177,7 @@ builtin_input_impl(PyObject *module, PyObject *prompt)
             Py_DECREF(tmp);
             if (fd < 0 && PyErr_Occurred())
                 goto error;
-            tty = fd == fileno(stdout) && isatty(fd);
+            tty = fd == fileno(stdout) && (isatty(fd) || is_cygpty(fd));
         }
     }
 
diff --git a/Python/dynamic_annotations.c b/Python/dynamic_annotations.c
index 7febaa09df1950..70d5b3dc72069c 100644
--- a/Python/dynamic_annotations.c
+++ b/Python/dynamic_annotations.c
@@ -27,7 +27,7 @@
  * Author: Kostya Serebryany
  */
 
-#ifdef _MSC_VER
+#ifdef MS_WINDOWS
 # include <windows.h>
 #endif
 
diff --git a/Python/dynload_win.c b/Python/dynload_win.c
index acab05e2c6def3..caa49681d175e9 100644
--- a/Python/dynload_win.c
+++ b/Python/dynload_win.c
@@ -4,6 +4,7 @@
 #include "Python.h"
 #include "pycore_fileutils.h"     // _Py_add_relfile()
 #include "pycore_pystate.h"       // _PyInterpreterState_GET()
+#include "pycore_initconfig.h"
 
 #ifdef HAVE_DIRECT_H
 #include <direct.h>
@@ -55,6 +56,16 @@ const char *_PyImport_DynLoadFiletab[] = {
 #define DWORD_AT(mem) (*(DWORD *)(mem))
 #define WORD_AT(mem)  (*(WORD *)(mem))
 
+#ifdef __MINGW32__
+#define DLL_PREFIX "libpython"
+#define DLL_PREFIX_LEN 9
+#define DLL_NAME_FORMAT "libpython%d.%d"
+#else
+#define DLL_PREFIX "python"
+#define DLL_PREFIX_LEN 6
+#define DLL_NAME_FORMAT "python%d%d"
+#endif
+
 static char *GetPythonImport (HINSTANCE hModule)
 {
     unsigned char *dllbase, *import_data, *import_name;
@@ -121,15 +132,15 @@ static char *GetPythonImport (HINSTANCE hModule)
                                          import_off);
         while (DWORD_AT(import_data)) {
             import_name = dllbase + DWORD_AT(import_data+12);
-            if (strlen(import_name) >= 6 &&
-                !strncmp(import_name,"python",6)) {
+            if (strlen(import_name) >= DLL_PREFIX_LEN &&
+                !strncmp(import_name, DLL_PREFIX, DLL_PREFIX_LEN)) {
                 char *pch;
 
                 /* Don't claim that python3.dll is a Python DLL. */
 #ifdef _DEBUG
-                if (strcmp(import_name, "python3_d.dll") == 0) {
+                if (strcmp(import_name, DLL_PREFIX "3_d.dll") == 0) {
 #else
-                if (strcmp(import_name, "python3.dll") == 0) {
+                if (strcmp(import_name, DLL_PREFIX "3.dll") == 0) {
 #endif
                     import_data += 20;
                     continue;
@@ -137,7 +148,7 @@ static char *GetPythonImport (HINSTANCE hModule)
 
                 /* Ensure python prefix is followed only
                    by numbers to the end of the basename */
-                pch = import_name + 6;
+                pch = import_name + DLL_PREFIX_LEN;
 #ifdef _DEBUG
                 while (*pch && pch[0] != '_' && pch[1] != 'd' && pch[2] != '.') {
 #else
@@ -171,8 +182,7 @@ static char *GetPythonImport (HINSTANCE hModule)
    Return whether the DLL was found.
 */
 extern HMODULE PyWin_DLLhModule;
-static int
-_Py_CheckPython3(void)
+int _Py_CheckPython3(void)
 {
     static int python3_checked = 0;
     static HANDLE hPython3;
@@ -226,14 +236,38 @@ dl_funcptr _PyImport_FindSharedFuncptrWindows(const char *prefix,
     dl_funcptr p;
     char funcname[258], *import_python;
 
-#ifdef Py_ENABLE_SHARED
-    _Py_CheckPython3();
-#endif /* Py_ENABLE_SHARED */
+    int use_legacy = 0;
+    DWORD load_library_flags = 0;
+
+    _Py_get_env_flag(1, &use_legacy, "PYTHONLEGACYWINDOWSDLLLOADING");
+
+    if (use_legacy) {
+        load_library_flags = LOAD_WITH_ALTERED_SEARCH_PATH;
+    } else {
+        load_library_flags = LOAD_LIBRARY_SEARCH_DEFAULT_DIRS |
+                              LOAD_LIBRARY_SEARCH_DLL_LOAD_DIR;
+    }
+
+#ifdef _MSC_VER
+    _Py_CheckPython3(); 
+#endif /* _MSC_VER */
+
+// So we can adjust the separators in the path below
+#define USE_UNICODE_WCHAR_CACHE 0
 
     wchar_t *wpathname = PyUnicode_AsWideCharString(pathname, NULL);
     if (wpathname == NULL)
         return NULL;
 
+    // LoadLibraryExW only considers paths using backslashes as "fully qualified",
+    // and for example LOAD_LIBRARY_SEARCH_DLL_LOAD_DIR doesn't work with forward slashes.
+    // https://github.com/msys2-contrib/cpython-mingw/issues/151
+    for (size_t i = 0; wpathname[i] != L'\0'; ++i) {
+        if (wpathname[i] == L'/') {
+            wpathname[i] = L'\\';
+        }
+    }
+
     PyOS_snprintf(funcname, sizeof(funcname), "%.20s_%.200s", prefix, shortname);
 
     {
@@ -250,9 +284,7 @@ dl_funcptr _PyImport_FindSharedFuncptrWindows(const char *prefix,
            AddDllDirectory function. We add SEARCH_DLL_LOAD_DIR to
            ensure DLLs adjacent to the PYD are preferred. */
         Py_BEGIN_ALLOW_THREADS
-        hDLL = LoadLibraryExW(wpathname, NULL,
-                              LOAD_LIBRARY_SEARCH_DEFAULT_DIRS |
-                              LOAD_LIBRARY_SEARCH_DLL_LOAD_DIR);
+        hDLL = LoadLibraryExW(wpathname, NULL, load_library_flags);
         Py_END_ALLOW_THREADS
         PyMem_Free(wpathname);
 
@@ -319,9 +351,9 @@ dl_funcptr _PyImport_FindSharedFuncptrWindows(const char *prefix,
 
             PyOS_snprintf(buffer, sizeof(buffer),
 #ifdef _DEBUG
-                          "python%d%d_d.dll",
+                          DLL_NAME_FORMAT "_d.dll",
 #else
-                          "python%d%d.dll",
+                          DLL_NAME_FORMAT ".dll",
 #endif
                           PY_MAJOR_VERSION,PY_MINOR_VERSION);
             import_python = GetPythonImport(hDLL);
diff --git a/Python/fileutils.c b/Python/fileutils.c
index c7521751cd26d1..aae41433515bf4 100644
--- a/Python/fileutils.c
+++ b/Python/fileutils.c
@@ -1,4 +1,5 @@
 #include "Python.h"
+#include "iscygpty.h"
 #include "pycore_fileutils.h"     // fileutils definitions
 #include "pycore_runtime.h"       // _PyRuntime
 #include "osdefs.h"               // SEP
@@ -77,7 +78,7 @@ _Py_device_encoding(int fd)
     int valid;
     Py_BEGIN_ALLOW_THREADS
     _Py_BEGIN_SUPPRESS_IPH
-    valid = isatty(fd);
+    valid = isatty(fd) || is_cygpty(fd);
     _Py_END_SUPPRESS_IPH
     Py_END_ALLOW_THREADS
     if (!valid)
@@ -1925,12 +1926,12 @@ _Py_write_impl(int fd, const void *buf, size_t count, int gil_held)
            depending on heap usage). */
         if (gil_held) {
             Py_BEGIN_ALLOW_THREADS
-            if (isatty(fd)) {
+            if (isatty(fd) || is_cygpty(fd)) {
                 count = 32767;
             }
             Py_END_ALLOW_THREADS
         } else {
-            if (isatty(fd)) {
+            if (isatty(fd) || is_cygpty(fd)) {
                 count = 32767;
             }
         }
@@ -2143,19 +2144,31 @@ int
 _Py_isabs(const wchar_t *path)
 {
 #ifdef MS_WINDOWS
+    // create a copy of path and replace all forward slashes with backslashes
+    // pathccskiproot does not handle forward slashes
+    wchar_t *path_copy = _wcsdup(path);
+    if (path_copy == NULL) {
+        return 0;
+    }
+    Py_NormalizeSepsPathcchW(path_copy);
+
     const wchar_t *tail;
-    HRESULT hr = PathCchSkipRoot(path, &tail);
-    if (FAILED(hr) || path == tail) {
+    HRESULT hr = PathCchSkipRoot(path_copy, &tail);
+    if (FAILED(hr) || path_copy == tail) {
+        free(path_copy);
         return 0;
     }
-    if (tail == &path[1] && (path[0] == SEP || path[0] == ALTSEP)) {
+    if (tail == &path_copy[1] && (path_copy[0] == SEP || path_copy[0] == ALTSEP)) {
         // Exclude paths with leading SEP
+        free(path_copy);
         return 0;
     }
-    if (tail == &path[2] && path[1] == L':') {
+    if (tail == &path_copy[2] && path_copy[1] == L':') {
         // Exclude drive-relative paths (e.g. C:filename.ext)
+        free(path_copy);
         return 0;
     }
+    free(path_copy);
     return 1;
 #else
     return (path[0] == SEP);
@@ -2188,7 +2201,11 @@ _Py_abspath(const wchar_t *path, wchar_t **abspath_p)
     }
 
 #ifdef MS_WINDOWS
-    return _PyOS_getfullpathname(path, abspath_p);
+    if (_PyOS_getfullpathname(path, abspath_p) < 0){
+        return -1;
+    }
+    *abspath_p = _Py_normpath(*abspath_p, -1);
+    return 0;
 #else
     wchar_t cwd[MAXPATHLEN + 1];
     cwd[Py_ARRAY_LENGTH(cwd) - 1] = 0;
@@ -2298,6 +2315,8 @@ join_relfile(wchar_t *buffer, size_t bufsize,
              const wchar_t *dirname, const wchar_t *relfile)
 {
 #ifdef MS_WINDOWS
+    Py_NormalizeSepsPathcchW(dirname);
+    Py_NormalizeSepsPathcchW(relfile);
     if (FAILED(PathCchCombineEx(buffer, bufsize, dirname, relfile,
         PATHCCH_ALLOW_LONG_PATHS))) {
         return -1;
@@ -2400,11 +2419,16 @@ _Py_normpath_and_size(wchar_t *path, Py_ssize_t size, Py_ssize_t *normsize)
     wchar_t *minP2 = path;  // the beginning of the destination range
     wchar_t lastC = L'\0';  // the last ljusted character, p2[-1] in most cases
 
+    const wchar_t sep = Py_GetSepW(NULL);
+#ifdef ALTSEP
+    const wchar_t altsep = Py_GetAltSepW(NULL);
+#endif
+
 #define IS_END(x) (pEnd ? (x) == pEnd : !*(x))
 #ifdef ALTSEP
-#define IS_SEP(x) (*(x) == SEP || *(x) == ALTSEP)
+#define IS_SEP(x) (*(x) == sep || *(x) == altsep)
 #else
-#define IS_SEP(x) (*(x) == SEP)
+#define IS_SEP(x) (*(x) == sep)
 #endif
 #define SEP_OR_END(x) (IS_SEP(x) || IS_END(x))
 
@@ -2415,7 +2439,7 @@ _Py_normpath_and_size(wchar_t *path, Py_ssize_t size, Py_ssize_t *normsize)
             path++;
         }
         p1 = p2 = minP2 = path;
-        lastC = SEP;
+        lastC = sep;
     }
 #ifdef MS_WINDOWS
     // Skip past drive segment and update minP2
@@ -2429,13 +2453,13 @@ _Py_normpath_and_size(wchar_t *path, Py_ssize_t size, Py_ssize_t *normsize)
     // and network paths, including the first segment.
     else if (IS_SEP(&p1[0]) && IS_SEP(&p1[1])) {
         int sepCount = 2;
-        *p2++ = SEP;
-        *p2++ = SEP;
+        *p2++ = sep;
+        *p2++ = sep;
         p1 += 2;
         for (; !IS_END(p1) && sepCount; ++p1) {
             if (IS_SEP(p1)) {
                 --sepCount;
-                *p2++ = lastC = SEP;
+                *p2++ = lastC = sep;
             } else {
                 *p2++ = lastC = *p1;
             }
@@ -2448,7 +2472,7 @@ _Py_normpath_and_size(wchar_t *path, Py_ssize_t size, Py_ssize_t *normsize)
         *p2++ = *p1++;
         *p2++ = *p1++;
         minP2 = p2 - 1;  // Absolute path has SEP at minP2
-        lastC = SEP;
+        lastC = sep;
     }
 #endif /* MS_WINDOWS */
 
@@ -2456,18 +2480,18 @@ _Py_normpath_and_size(wchar_t *path, Py_ssize_t size, Py_ssize_t *normsize)
     for (; !IS_END(p1); ++p1) {
         wchar_t c = *p1;
 #ifdef ALTSEP
-        if (c == ALTSEP) {
-            c = SEP;
+        if (c == altsep) {
+            c = sep;
         }
 #endif
-        if (lastC == SEP) {
+        if (lastC == sep) {
             if (c == L'.') {
                 int sep_at_1 = SEP_OR_END(&p1[1]);
                 int sep_at_2 = !sep_at_1 && SEP_OR_END(&p1[2]);
                 if (sep_at_2 && p1[1] == L'.') {
                     wchar_t *p3 = p2;
-                    while (p3 != minP2 && *--p3 == SEP) { }
-                    while (p3 != minP2 && *(p3 - 1) != SEP) { --p3; }
+                    while (p3 != minP2 && *--p3 == sep) { }
+                    while (p3 != minP2 && *(p3 - 1) != sep) { --p3; }
                     if (p2 == minP2
                         || (p3[0] == L'.' && p3[1] == L'.' && IS_SEP(&p3[2])))
                     {
@@ -2476,7 +2500,7 @@ _Py_normpath_and_size(wchar_t *path, Py_ssize_t size, Py_ssize_t *normsize)
                         *p2++ = L'.';
                         *p2++ = L'.';
                         lastC = L'.';
-                    } else if (p3[0] == SEP) {
+                    } else if (p3[0] == sep) {
                         // Absolute path, so absorb segment
                         p2 = p3 + 1;
                     } else {
@@ -2487,7 +2511,7 @@ _Py_normpath_and_size(wchar_t *path, Py_ssize_t size, Py_ssize_t *normsize)
                 } else {
                     *p2++ = lastC = c;
                 }
-            } else if (c == SEP) {
+            } else if (c == sep) {
             } else {
                 *p2++ = lastC = c;
             }
@@ -2497,7 +2521,7 @@ _Py_normpath_and_size(wchar_t *path, Py_ssize_t size, Py_ssize_t *normsize)
     }
     *p2 = L'\0';
     if (p2 != minP2) {
-        while (--p2 != minP2 && *p2 == SEP) {
+        while (--p2 != minP2 && *p2 == sep) {
             *p2 = L'\0';
         }
     } else {
diff --git a/Python/frozenmain.c b/Python/frozenmain.c
index f8be165f7671df..d18c7b3884c27b 100644
--- a/Python/frozenmain.c
+++ b/Python/frozenmain.c
@@ -3,6 +3,7 @@
 #include "Python.h"
 #include "pycore_runtime.h"  // _PyRuntime_Initialize()
 #include <locale.h>
+#include "iscygpty.h"
 
 #ifdef MS_WINDOWS
 extern void PyWinFreeze_ExeInit(void);
@@ -71,7 +72,7 @@ Py_FrozenMain(int argc, char **argv)
         sts = 0;
     }
 
-    if (inspect && isatty((int)fileno(stdin))) {
+    if (inspect && (isatty((int)fileno(stdin)) || is_cygpty((int)fileno(stdin))))
         sts = PyRun_AnyFile(stdin, "<stdin>") != 0;
     }
 
diff --git a/Python/getcompiler.c b/Python/getcompiler.c
index a5d26239e8772e..dd4d3c8f101468 100644
--- a/Python/getcompiler.c
+++ b/Python/getcompiler.c
@@ -7,10 +7,45 @@
 
 // Note the __clang__ conditional has to come before the __GNUC__ one because
 // clang pretends to be GCC.
-#if defined(__clang__)
+#if defined(__clang__) && !defined(_WIN32)
 #define COMPILER "[Clang " __clang_version__ "]"
 #elif defined(__GNUC__)
-#define COMPILER "[GCC " __VERSION__ "]"
+/* To not break compatibility with things that determine
+   CPU arch by calling get_build_version in msvccompiler.py
+   (such as NumPy) add "32 bit" or "64 bit (AMD64)" on Windows
+   and also use a space as a separator rather than a newline. */
+#if defined(_WIN32)
+#define COMP_SEP " "
+#if defined(__x86_64__)
+#define ARCH_SUFFIX " 64 bit (AMD64)"
+#elif defined(__aarch64__)
+#define ARCH_SUFFIX " 64 bit (ARM64)"
+#elif defined(__arm__)
+#define ARCH_SUFFIX " 32 bit (ARM)"
+#else
+#define ARCH_SUFFIX " 32 bit"
+#endif
+#else
+#define COMP_SEP "\n"
+#define ARCH_SUFFIX ""
+#endif
+#if defined(__clang__)
+#define str(x) #x
+#define xstr(x) str(x)
+#if defined(_UCRT)
+#define COMPILER COMP_SEP "[GCC UCRT Clang " xstr(__clang_major__) "." \
+        xstr(__clang_minor__) "." xstr(__clang_patchlevel__) ARCH_SUFFIX "]"
+#else
+#define COMPILER COMP_SEP "[GCC Clang " xstr(__clang_major__) "." \
+        xstr(__clang_minor__) "." xstr(__clang_patchlevel__) ARCH_SUFFIX "]"
+#endif
+#else
+#if defined(_UCRT)
+#define COMPILER COMP_SEP "[GCC UCRT " __VERSION__ ARCH_SUFFIX "]"
+#else
+#define COMPILER COMP_SEP "[GCC " __VERSION__ ARCH_SUFFIX "]"
+#endif
+#endif
 // Generic fallbacks.
 #elif defined(__cplusplus)
 #define COMPILER "[C++]"
diff --git a/Python/initconfig.c b/Python/initconfig.c
index ed4c4e23f34a80..6ba6f5bfc863b5 100644
--- a/Python/initconfig.c
+++ b/Python/initconfig.c
@@ -164,7 +164,7 @@ static const char usage_envvars[] =
 "PYTHONWARNINGS  : warning control (-W)\n"
 ;
 
-#if defined(MS_WINDOWS)
+#if defined(_MSC_VER)
 #  define PYTHONHOMEHELP "<prefix>\\python{major}{minor}"
 #else
 #  define PYTHONHOMEHELP "<prefix>/lib/pythonX.X"
diff --git a/Python/iscygpty.c b/Python/iscygpty.c
new file mode 100644
index 00000000000000..722f88f2f46dcb
--- /dev/null
+++ b/Python/iscygpty.c
@@ -0,0 +1,185 @@
+/*
+ * iscygpty.c -- part of ptycheck
+ * https://github.com/k-takata/ptycheck
+ *
+ * Copyright (c) 2015-2017 K.Takata
+ *
+ * You can redistribute it and/or modify it under the terms of either
+ * the MIT license (as described below) or the Vim license.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+ * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+ * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#ifdef _WIN32
+
+#include <ctype.h>
+#include <io.h>
+#include <wchar.h>
+#include <windows.h>
+
+#ifdef USE_FILEEXTD
+/* VC 7.1 or earlier doesn't support SAL. */
+# if !defined(_MSC_VER) || (_MSC_VER < 1400)
+#  define __out
+#  define __in
+#  define __in_opt
+# endif
+/* Win32 FileID API Library:
+ * http://www.microsoft.com/en-us/download/details.aspx?id=22599
+ * Needed for WinXP. */
+# include <fileextd.h>
+#else /* USE_FILEEXTD */
+/* VC 8 or earlier. */
+# if defined(_MSC_VER) && (_MSC_VER < 1500)
+#  ifdef ENABLE_STUB_IMPL
+#   define STUB_IMPL
+#  else
+#   error "Win32 FileID API Library is required for VC2005 or earlier."
+#  endif
+# endif
+#endif /* USE_FILEEXTD */
+
+
+#include "iscygpty.h"
+
+//#define USE_DYNFILEID
+#ifdef USE_DYNFILEID
+typedef BOOL (WINAPI *pfnGetFileInformationByHandleEx)(
+		HANDLE                    hFile,
+		FILE_INFO_BY_HANDLE_CLASS FileInformationClass,
+		LPVOID                    lpFileInformation,
+		DWORD                     dwBufferSize
+);
+static pfnGetFileInformationByHandleEx pGetFileInformationByHandleEx = NULL;
+
+# ifndef USE_FILEEXTD
+static BOOL WINAPI stub_GetFileInformationByHandleEx(
+		HANDLE                    hFile,
+		FILE_INFO_BY_HANDLE_CLASS FileInformationClass,
+		LPVOID                    lpFileInformation,
+		DWORD                     dwBufferSize
+		)
+{
+	return FALSE;
+}
+# endif
+
+static void setup_fileid_api(void)
+{
+	if (pGetFileInformationByHandleEx != NULL) {
+		return;
+	}
+	pGetFileInformationByHandleEx = (pfnGetFileInformationByHandleEx)
+		GetProcAddress(GetModuleHandle(TEXT("kernel32.dll")),
+				"GetFileInformationByHandleEx");
+	if (pGetFileInformationByHandleEx == NULL) {
+# ifdef USE_FILEEXTD
+		pGetFileInformationByHandleEx = GetFileInformationByHandleEx;
+# else
+		pGetFileInformationByHandleEx = stub_GetFileInformationByHandleEx;
+# endif
+	}
+}
+#else
+# define pGetFileInformationByHandleEx	GetFileInformationByHandleEx
+# define setup_fileid_api()
+#endif
+
+
+#define is_wprefix(s, prefix) \
+	(wcsncmp((s), (prefix), sizeof(prefix) / sizeof(WCHAR) - 1) == 0)
+
+/* Check if the fd is a cygwin/msys's pty. */
+int is_cygpty(int fd)
+{
+#ifdef STUB_IMPL
+	return 0;
+#else
+	HANDLE h;
+	int size = sizeof(FILE_NAME_INFO) + sizeof(WCHAR) * (MAX_PATH - 1);
+	FILE_NAME_INFO *nameinfo;
+	WCHAR *p = NULL;
+
+	setup_fileid_api();
+
+	h = (HANDLE) _get_osfhandle(fd);
+	if (h == INVALID_HANDLE_VALUE) {
+		return 0;
+	}
+	/* Cygwin/msys's pty is a pipe. */
+	if (GetFileType(h) != FILE_TYPE_PIPE) {
+		return 0;
+	}
+	nameinfo = malloc(size + sizeof(WCHAR));
+	if (nameinfo == NULL) {
+		return 0;
+	}
+	/* Check the name of the pipe:
+	 * '\{cygwin,msys}-XXXXXXXXXXXXXXXX-ptyN-{from,to}-master' */
+	if (pGetFileInformationByHandleEx(h, FileNameInfo, nameinfo, size)) {
+		nameinfo->FileName[nameinfo->FileNameLength / sizeof(WCHAR)] = L'\0';
+		p = nameinfo->FileName;
+		if (is_wprefix(p, L"\\cygwin-")) {		/* Cygwin */
+			p += 8;
+		} else if (is_wprefix(p, L"\\msys-")) {	/* MSYS and MSYS2 */
+			p += 6;
+		} else {
+			p = NULL;
+		}
+		if (p != NULL) {
+			while (*p && isxdigit(*p))	/* Skip 16-digit hexadecimal. */
+				++p;
+			if (is_wprefix(p, L"-pty")) {
+				p += 4;
+			} else {
+				p = NULL;
+			}
+		}
+		if (p != NULL) {
+			while (*p && isdigit(*p))	/* Skip pty number. */
+				++p;
+			if (is_wprefix(p, L"-from-master")) {
+				//p += 12;
+			} else if (is_wprefix(p, L"-to-master")) {
+				//p += 10;
+			} else {
+				p = NULL;
+			}
+		}
+	}
+	free(nameinfo);
+	return (p != NULL);
+#endif /* STUB_IMPL */
+}
+
+/* Check if at least one cygwin/msys pty is used. */
+int is_cygpty_used(void)
+{
+	int fd, ret = 0;
+
+	for (fd = 0; fd < 3; fd++) {
+		ret |= is_cygpty(fd);
+	}
+	return ret;
+}
+
+#endif /* _WIN32 */
+
+/* vim: set ts=4 sw=4: */
diff --git a/Python/pathconfig.c b/Python/pathconfig.c
index be0f97c4b204a9..7eb9006be5b40a 100644
--- a/Python/pathconfig.c
+++ b/Python/pathconfig.c
@@ -2,7 +2,7 @@
 
 #include "Python.h"
 #include "marshal.h"              // PyMarshal_ReadObjectFromString
-#include "osdefs.h"               // DELIM
+#include "osdefs.h"               // DELIM, SEP
 #include "pycore_initconfig.h"
 #include "pycore_fileutils.h"
 #include "pycore_pathconfig.h"
@@ -18,6 +18,158 @@
 extern "C" {
 #endif
 
+#ifdef __MINGW32__
+#define wcstok  wcstok_s
+#include <windows.h>
+#endif
+
+static int
+Py_StartsWithA(const char * str, const char * prefix)
+{
+    while(*prefix)
+    {
+        if(*prefix++ != *str++)
+            return 0;
+    }
+
+    return 1;
+}
+
+static int
+Py_StartsWithW(const wchar_t * str, const wchar_t * prefix)
+{
+    while(*prefix)
+    {
+        if(*prefix++ != *str++)
+            return 0;
+    }
+
+    return 1;
+}
+
+char
+Py_GetSepA(const char *name)
+{
+    static char sep = '\0';
+#ifdef _WIN32
+    /* https://msdn.microsoft.com/en-gb/library/windows/desktop/aa365247%28v=vs.85%29.aspx
+     * The "\\?\" prefix .. indicate that the path should be passed to the system with minimal
+     * modification, which means that you cannot use forward slashes to represent path separators
+     */
+    if (name != NULL && Py_StartsWithA(name, "\\\\?\\") != 0)
+    {
+        return '\\';
+    }
+#endif
+    if (sep != '\0')
+        return sep;
+#if defined(__MINGW32__)
+    char* msystem = getenv("MSYSTEM");
+    if (msystem != NULL && strcmp(msystem, "") != 0)
+        sep = '/';
+    else
+        sep = '\\';
+#else
+    sep = SEP;
+#endif
+    return sep;
+}
+
+static char
+Py_GetAltSepA(const char *name)
+{
+    char sep = Py_GetSepA(name);
+    if (sep == '/')
+        return '\\';
+    return '/';
+}
+
+void
+Py_NormalizeSepsA(char *name)
+{
+    assert(name != NULL);
+    char sep = Py_GetSepA(name);
+    char altsep = Py_GetAltSepA(name);
+    char* seps;
+    if (name[0] != '\0' && name[1] == ':') {
+        name[0] = toupper(name[0]);
+    }
+    seps = strchr(name, altsep);
+    while(seps) {
+        *seps = sep;
+        seps = strchr(seps, altsep);
+    }
+}
+
+wchar_t
+Py_GetSepW(const wchar_t *name)
+{
+    static wchar_t sep = L'\0';
+#ifdef _WIN32
+    /* https://msdn.microsoft.com/en-gb/library/windows/desktop/aa365247%28v=vs.85%29.aspx
+     * The "\\?\" prefix .. indicate that the path should be passed to the system with minimal
+     * modification, which means that you cannot use forward slashes to represent path separators
+     */
+    if (name != NULL && Py_StartsWithW(name, L"\\\\?\\") != 0)
+    {
+        return L'\\';
+    }
+#endif
+    if (sep != L'\0')
+        return sep;
+#if defined(__MINGW32__)
+    char* msystem = getenv("MSYSTEM");
+    if (msystem != NULL && strcmp(msystem, "") != 0)
+        sep = L'/';
+    else
+        sep = L'\\';
+#else
+    sep = SEP;
+#endif
+    return sep;
+}
+
+wchar_t
+Py_GetAltSepW(const wchar_t *name)
+{
+    char sep = Py_GetSepW(name);
+    if (sep == L'/')
+        return L'\\';
+    return L'/';
+}
+
+void
+Py_NormalizeSepsW(wchar_t *name)
+{
+    assert(name != NULL);
+    wchar_t sep = Py_GetSepW(name);
+    wchar_t altsep = Py_GetAltSepW(name);
+    wchar_t* seps;
+    if (name[0] != L'\0' && name[1] == L':') {
+        name[0] = towupper(name[0]);
+    }
+    seps = wcschr(name, altsep);
+    while(seps) {
+        *seps = sep;
+        seps = wcschr(seps, altsep);
+    }
+}
+
+void
+Py_NormalizeSepsPathcchW(wchar_t *name)
+{
+#ifdef MS_WINDOWS
+    assert(name != NULL);
+    wchar_t sep = '\\';
+    wchar_t altsep = '/';
+    wchar_t* seps;
+    seps = wcschr(name, altsep);
+    while(seps) {
+        *seps = sep;
+        seps = wcschr(seps, altsep);
+    }
+#endif
+}
 
 /* External interface */
 
@@ -317,6 +469,7 @@ _Py_SetProgramFullPath(const wchar_t *program_full_path)
     if (has_value && _Py_path_config.program_full_path == NULL) {
         path_out_of_memory(__func__);
     }
+    Py_NormalizeSepsW(_Py_path_config.program_name);
 }
 
 
@@ -509,7 +662,7 @@ _PyPathConfig_ComputeSysPath0(const PyWideStringList *argv, PyObject **path0_p)
     }
 #endif /* All others */
 
-    PyObject *path0_obj = PyUnicode_FromWideChar(path0, n);
+    PyObject *path0_obj = PyUnicode_FromWideChar(_Py_normpath(path0, -1), n);
     if (path0_obj == NULL) {
         return -1;
     }
diff --git a/Python/pylifecycle.c b/Python/pylifecycle.c
index f5bea14b16b401..0bbb279511a3e5 100644
--- a/Python/pylifecycle.c
+++ b/Python/pylifecycle.c
@@ -30,6 +30,7 @@
 #include "pycore_unicodeobject.h" // _PyUnicode_InitTypes()
 #include "opcode.h"
 
+#include "iscygpty.h"
 #include <locale.h>               // setlocale()
 #include <stdlib.h>               // getenv()
 
@@ -3113,7 +3114,7 @@ Py_Exit(int sts)
 int
 Py_FdIsInteractive(FILE *fp, const char *filename)
 {
-    if (isatty(fileno(fp))) {
+    if (isatty(fileno(fp)) || is_cygpty(fileno(fp))) {
         return 1;
     }
     if (!_Py_GetConfig()->interactive) {
@@ -3128,7 +3129,7 @@ Py_FdIsInteractive(FILE *fp, const char *filename)
 int
 _Py_FdIsInteractive(FILE *fp, PyObject *filename)
 {
-    if (isatty(fileno(fp))) {
+    if (isatty(fileno(fp)) || is_cygpty(fileno(fp))) {
         return 1;
     }
     if (!_Py_GetConfig()->interactive) {
diff --git a/Python/sysmodule.c b/Python/sysmodule.c
index 6ed28ec5fbd8ba..0182569172b9dd 100644
--- a/Python/sysmodule.c
+++ b/Python/sysmodule.c
@@ -45,7 +45,7 @@ Data members:
 #  include <windows.h>
 #endif /* MS_WINDOWS */
 
-#ifdef MS_COREDLL
+#if defined(MS_WINDOWS) && defined(Py_ENABLE_SHARED)
 extern void *PyWin_DLLhModule;
 /* A string loaded from the DLL at startup: */
 extern const char *PyWin_DLLVersionString;
@@ -3429,7 +3429,7 @@ _PySys_InitCore(PyThreadState *tstate, PyObject *sysdict)
     SET_SYS_FROM_STRING("byteorder", "little");
 #endif
 
-#ifdef MS_COREDLL
+#if defined(MS_WINDOWS) && defined(Py_ENABLE_SHARED)
     SET_SYS("dllhandle", PyLong_FromVoidPtr(PyWin_DLLhModule));
     SET_SYS_FROM_STRING("winver", PyWin_DLLVersionString);
 #endif
diff --git a/Python/traceback.c b/Python/traceback.c
index 1cb82c57203758..37df982bb737f3 100644
--- a/Python/traceback.c
+++ b/Python/traceback.c
@@ -342,7 +342,7 @@ _Py_FindSourceFile(PyObject *filename, char* namebuf, size_t namelen, PyObject *
     filepath = PyBytes_AS_STRING(filebytes);
 
     /* Search tail of filename in sys.path before giving up */
-    tail = strrchr(filepath, SEP);
+    tail = strrchr(filepath, Py_GetSepA(filepath));
     if (tail == NULL)
         tail = filepath;
     else
diff --git a/Tools/build/check_extension_modules.py b/Tools/build/check_extension_modules.py
index aa1ade71a8e937..7ded0f464c205d 100644
--- a/Tools/build/check_extension_modules.py
+++ b/Tools/build/check_extension_modules.py
@@ -61,6 +61,10 @@
     "winsound",
 }
 
+if sys.platform == "win32":
+    # Enable DLL loading from PATH.
+    os.environ["PYTHONLEGACYWINDOWSDLLLOADING"] = "1"
+
 
 logger = logging.getLogger(__name__)
 
diff --git a/configure.ac b/configure.ac
index 1a02d19f1b2a3f..5dcec81ce13d23 100644
--- a/configure.ac
+++ b/configure.ac
@@ -12,7 +12,7 @@ dnl
 # Set VERSION so we only need to edit in one place (i.e., here)
 m4_define([PYTHON_VERSION], [3.12])
 
-AC_PREREQ([2.71])
+AC_PREREQ([2.69])
 
 AC_INIT([python],[PYTHON_VERSION],[https://github.com/python/cpython/issues/])
 
@@ -204,9 +204,11 @@ AC_SUBST([FREEZE_MODULE])
 AC_SUBST([FREEZE_MODULE_DEPS])
 AC_SUBST([PYTHON_FOR_BUILD_DEPS])
 
+NATIVE_PYTHON_SEARCH_PATH_MINGW=`echo $host | grep -Eq 'mingw*' && echo "$MINGW_PREFIX/bin" || echo $PATH`
 AC_CHECK_PROGS([PYTHON_FOR_REGEN],
   [python$PACKAGE_VERSION python3.12 python3.11 python3.10 python3 python],
-  [python3])
+  [python3],
+  [$NATIVE_PYTHON_SEARCH_PATH_MINGW])
 AC_SUBST([PYTHON_FOR_REGEN])
 
 AC_MSG_CHECKING([Python for regen version])
@@ -550,6 +552,9 @@ then
 	*-*-cygwin*)
 		ac_sys_system=Cygwin
 		;;
+	*-*-mingw*)
+		ac_sys_system=MINGW
+		;;
 	*-*-vxworks*)
 	    ac_sys_system=VxWorks
 	    ;;
@@ -585,6 +590,7 @@ then
 	linux*) MACHDEP="linux";;
 	cygwin*) MACHDEP="cygwin";;
 	darwin*) MACHDEP="darwin";;
+	mingw*) MACHDEP="win32";;
 	'')	MACHDEP="unknown";;
     esac
 
@@ -618,6 +624,9 @@ if test "$cross_compiling" = yes; then
 		;;
 	wasm32-*-* | wasm64-*-*)
 		_host_cpu=$host_cpu
+    ;;
+	*-*-mingw*)
+		_host_cpu=
 		;;
 	*)
 		# for now, limit cross builds to known configurations
@@ -625,6 +634,14 @@ if test "$cross_compiling" = yes; then
 		AC_MSG_ERROR([cross build not supported for $host])
 	esac
 	_PYTHON_HOST_PLATFORM="$MACHDEP${_host_cpu:+-$_host_cpu}"
+
+	case "$host_os" in
+	mingw*)
+	# As sys.platform() return 'win32' to build python and extantions
+	# we will use 'mingw' (in setup.py and etc.)
+	_PYTHON_HOST_PLATFORM=mingw
+	;;
+	esac
 fi
 
 # Some systems cannot stand _XOPEN_SOURCE being defined at all; they
@@ -740,6 +757,65 @@ then
             [Define to include mbstate_t for mbrtowc])
 fi
 
+# On 'semi-native' build systems (MSYS*/Cygwin targeting MinGW-w64)
+# _sysconfigdata.py will contain paths that are correct only in the
+# build environment. This means external modules will fail to build
+# without setting up the same env and also that the build of Python
+# itself will fail as the paths are not correct for the host tools.
+#
+# To work around these issues a set of _b2h variables are created:
+# prefix_b2h, srcdir_b2h, abs_srcdir_b2h
+# and abs_builddir_b2h
+# .. where b2h stands for build to host. sysconfig.py replaces path
+# prefixes matching the non-b2h versions with the b2h equivalents.
+#
+# (note this assumes the host compilers are native and *not* cross
+#  - in the 'semi-native' scenario only that is.)
+
+AC_DEFUN([ABS_PATH_HOST],
+[$1=$(cd $$2 && pwd)
+  case $build_os in
+    mingw*)
+      case $host_os in
+        mingw*) $1=$(cd $$2 && pwd -W) ;;
+        *) ;;
+      esac
+      ;;
+    cygwin*)
+      case $host_os in
+        mingw*) $1=$(cygpath -w -m $$2) ;;
+        *) ;;
+      esac
+      ;;
+  esac
+AC_SUBST([$1])
+])
+
+AC_MSG_CHECKING(absolute host location of prefix)
+ABS_PATH_HOST([prefix_b2h],[prefix])
+AC_MSG_RESULT([$prefix_b2h])
+
+AC_MSG_CHECKING(absolute host location of srcdir)
+ABS_PATH_HOST([srcdir_b2h],[srcdir])
+AC_MSG_RESULT([$srcdir_b2h])
+
+AC_MSG_CHECKING(absolute host location of abs_srcdir)
+ABS_PATH_HOST([abs_srcdir_b2h],[srcdir])
+AC_MSG_RESULT([$abs_srcdir_b2h])
+
+my_builddir=.
+AC_MSG_CHECKING(Absolute host location of abs_builddir)
+ABS_PATH_HOST([abs_builddir_b2h],[my_builddir])
+AC_MSG_RESULT([$abs_builddir_b2h])
+
+AC_MSG_CHECKING([for init system calls])
+AC_SUBST(INITSYS)
+case $host in
+  *-*-mingw*)	INITSYS=nt;;
+  *)		INITSYS=posix;;
+esac
+AC_MSG_RESULT([$INITSYS])
+
 # Record the configure-time value of MACOSX_DEPLOYMENT_TARGET,
 # it may influence the way we can build extensions, so distutils
 # needs to check it
@@ -1190,6 +1266,28 @@ AC_CACHE_CHECK([for -Wl,--no-as-needed], [ac_cv_wl_no_as_needed], [
 ])
 AC_SUBST([NO_AS_NEEDED])
 
+# initialize default configuration
+py_config=
+case $host in
+  *-*-mingw*) py_config=mingw ;;
+esac
+if test -n "$py_config" ; then
+  AC_MSG_NOTICE([loading configure defaults from .../Misc/config_$py_config"])
+  . "$srcdir/Misc/config_$py_config"
+fi
+
+# initialize defaults for cross-builds
+if test "$cross_compiling" = yes; then
+  py_config=$host_os
+  case $py_config in
+    mingw32*) py_config=mingw32 ;;
+  esac
+  if test -f "$srcdir/Misc/cross_$py_config" ; then
+    AC_MSG_NOTICE([loading cross defaults from .../Misc/cross_$py_config"])
+    . "$srcdir/Misc/cross_$py_config"
+  fi
+fi
+
 AC_MSG_CHECKING([for the Android API level])
 cat > conftest.c <<EOF
 #ifdef __ANDROID__
@@ -1303,6 +1401,7 @@ AC_ARG_WITH([suffix],
     [Emscripten/browser*], [EXEEXT=.js],
     [Emscripten/node*], [EXEEXT=.js],
     [WASI/*], [EXEEXT=.wasm],
+    [MINGW*], [EXEEXT=.exe],
     [EXEEXT=]
   )
 ])
@@ -1329,6 +1428,10 @@ else
 fi
 rmdir CaseSensitiveTestDir
 
+AS_CASE([$ac_sys_system],
+  [MINGW], [BUILDEXEEXT=".exe"]
+)
+
 case $ac_sys_system in
 hp*|HP*)
     case $CC in
@@ -1507,6 +1610,11 @@ if test $enable_shared = "yes"; then
           LDLIBRARY='libpython$(LDVERSION).dll.a'
           DLLLIBRARY='libpython$(LDVERSION).dll'
           ;;
+    MINGW*)
+          LDLIBRARY='libpython$(LDVERSION).dll.a'
+          DLLLIBRARY='libpython$(LDVERSION).dll'
+          BLDLIBRARY='-L. -lpython$(LDVERSION)'
+          ;;
     SunOS*)
 	  LDLIBRARY='libpython$(LDVERSION).so'
 	  BLDLIBRARY='-Wl,-R,$(LIBDIR) -L. -lpython$(LDVERSION)'
@@ -1557,6 +1665,9 @@ else # shared is disabled
           BLDLIBRARY='$(LIBRARY)'
           LDLIBRARY='libpython$(LDVERSION).dll.a'
           ;;
+    MINGW*)
+          LDLIBRARY='libpython$(LDVERSION).a'
+          ;;
   esac
 fi
 
@@ -1650,6 +1761,10 @@ AC_SUBST([LINK_PYTHON_OBJS])
 AC_SUBST([AR])
 AC_CHECK_TOOLS([AR], [ar aal], [ar])
 
+# windres program
+AC_SUBST(WINDRES)
+AC_CHECK_TOOL(WINDRES, windres)
+
 # tweak ARFLAGS only if the user didn't set it on the command line
 AC_SUBST([ARFLAGS])
 if test -z "$ARFLAGS"
@@ -2413,6 +2528,14 @@ case $GCC in
 yes)
     CFLAGS_NODIST="$CFLAGS_NODIST -std=c11"
 
+    # GCC 14 and later error out with incompatible-pointer-types
+    # this only occues on mingw
+    case $host in
+    *-*-mingw*)
+        CFLAGS_NODIST="$CFLAGS_NODIST -Wno-error=incompatible-pointer-types"
+      ;;
+    esac
+
     PY_CHECK_CC_WARNING([enable], [extra], [if we can add -Wextra])
     AS_VAR_IF([ac_cv_enable_extra_warning], [yes],
               [CFLAGS_NODIST="$CFLAGS_NODIST -Wextra"])
@@ -2721,6 +2844,53 @@ then
 	BASECFLAGS="$BASECFLAGS $ac_arch_flags"
 fi
 
+dnl NOTE:
+dnl - GCC 4.4+ for mingw* require and use posix threads(pthreads-w32)
+dnl - Host may contain installed pthreads-w32.
+dnl - On windows platform only NT-thread model is supported. 
+dnl To avoid miss detection scipt first will check for NT-thread model
+dnl and if is not found will try to detect build options for pthread
+dnl model. Autodetection could be overiden if variable with_nt_threads
+dnl is set in "Site Configuration" (see autoconf manual).
+dnl If NT-thread model is enabled script skips some checks that
+dnl impact build process. When a new functionality is added, developers
+dnl are responsible to update configure script to avoid thread models
+dnl to be mixed.
+
+AC_MSG_CHECKING([for --with-nt-threads])
+AC_ARG_WITH(nt-threads,
+            AS_HELP_STRING([--with-nt-threads], [build with windows threads (default is system-dependent)]),
+[
+	case $withval in
+	no)	with_nt_threads=no;;
+	yes)	with_nt_threads=yes;;
+	*)	with_nt_threads=yes;;
+	esac
+], [
+	case $host in
+		*-*-mingw*) with_nt_threads=yes;;
+		*) with_nt_threads=no;;
+	esac
+])
+AC_MSG_RESULT([$with_nt_threads])
+
+if test $with_nt_threads = yes ; then
+AC_MSG_CHECKING([whether linking with nt-threads work])
+AC_LINK_IFELSE([
+    AC_LANG_PROGRAM([[#include <process.h>]],[[_beginthread(0, 0, 0);]])
+  ],
+  [AC_MSG_RESULT([yes])],
+  [AC_MSG_ERROR([failed to link with nt-threads])])
+fi
+
+if test $with_nt_threads = yes ; then
+  dnl temporary default flag to avoid additional pthread checks
+  dnl and initilize other ac..thread flags to no
+  ac_cv_pthread_is_default=no
+  ac_cv_kthread=no
+  ac_cv_pthread=no
+  dnl ac_cv_kpthread is set to no if default is yes (see below)
+else
 # On some compilers, pthreads are available without further options
 # (e.g. MacOS X). On some of these systems, the compiler will not
 # complain if unaccepted options are passed (e.g. gcc on Mac OS X).
@@ -2832,6 +3002,8 @@ int main(void){
 CC="$ac_save_cc"])
 fi
 
+fi
+
 # If we have set a CC compiler flag for thread support then
 # check if it works for CXX, too.
 if test ! -z "$CXX"
@@ -2851,6 +3023,10 @@ elif test "$ac_cv_pthread" = "yes"
 then
   CXX="$CXX -pthread"
   ac_cv_cxx_thread=yes
+elif test "$with_nt_threads" = "yes"
+then
+  dnl set to always to skip extra pthread check below
+  ac_cv_cxx_thread=always
 else
   ac_cv_cxx_thread=no
 fi
@@ -2889,11 +3065,11 @@ AC_DEFINE([STDC_HEADERS], [1],
 
 # checks for header files
 AC_CHECK_HEADERS([ \
-  alloca.h asm/types.h bluetooth.h conio.h crypt.h direct.h dlfcn.h endian.h errno.h fcntl.h grp.h \
+  alloca.h asm/types.h bluetooth.h conio.h crypt.h direct.h endian.h errno.h fcntl.h grp.h \
   ieeefp.h io.h langinfo.h libintl.h libutil.h linux/auxvec.h sys/auxv.h linux/fs.h linux/limits.h linux/memfd.h \
   linux/random.h linux/soundcard.h \
-  linux/tipc.h linux/wait.h netdb.h net/ethernet.h netinet/in.h netpacket/packet.h poll.h process.h pthread.h pty.h \
-  sched.h setjmp.h shadow.h signal.h spawn.h stropts.h sys/audioio.h sys/bsdtty.h sys/devpoll.h \
+  linux/tipc.h linux/wait.h netdb.h net/ethernet.h netinet/in.h netpacket/packet.h poll.h process.h pty.h \
+  setjmp.h shadow.h signal.h spawn.h stropts.h sys/audioio.h sys/bsdtty.h sys/devpoll.h \
   sys/endian.h sys/epoll.h sys/event.h sys/eventfd.h sys/file.h sys/ioctl.h sys/kern_control.h \
   sys/loadavg.h sys/lock.h sys/memfd.h sys/mkdev.h sys/mman.h sys/modem.h sys/param.h sys/pidfd.h sys/poll.h \
   sys/random.h sys/resource.h sys/select.h sys/sendfile.h sys/socket.h sys/soundcard.h sys/stat.h \
@@ -2901,9 +3077,24 @@ AC_CHECK_HEADERS([ \
   sys/types.h sys/uio.h sys/un.h sys/utsname.h sys/wait.h sys/xattr.h sysexits.h syslog.h \
   termios.h util.h utime.h utmp.h \
 ])
+
+case $host in
+  *-*-mingw*) ;;
+  *) AC_CHECK_HEADERS([dlfcn.h]);;
+esac
+
+
 AC_HEADER_DIRENT
 AC_HEADER_MAJOR
 
+# If using nt threads, don't look for pthread.h or thread.h
+if test "x$with_nt_threads" = xno ; then
+AC_HEADER_STDC
+AC_CHECK_HEADERS(pthread.h sched.h thread.h)
+AC_HEADER_DIRENT
+AC_HEADER_MAJOR
+fi
+
 # bluetooth/bluetooth.h has been known to not compile with -std=c99.
 # http://permalink.gmane.org/gmane.linux.bluez.kernel/22294
 SAVE_CFLAGS=$CFLAGS
@@ -3086,6 +3277,10 @@ dnl LFS does not work with Emscripten 3.1
 AS_CASE([$ac_sys_system],
   [Emscripten], [have_largefile_support="no"]
 )
+dnl Activate on windows platforms (32&64-bit) where off_t(4) < fpos_t(8)
+AS_CASE([$ac_sys_system],
+  [MINGW], [have_largefile_support="yes"]
+)
 AS_VAR_IF([have_largefile_support], [yes], [
   AC_DEFINE([HAVE_LARGEFILE_SUPPORT], [1],
   [Defined to enable large file support when an off_t is bigger than a long
@@ -3116,6 +3311,10 @@ elif test "$ac_cv_pthread" = "yes"
 then CC="$CC -pthread"
 fi
 
+if test $with_nt_threads = yes ; then
+  dnl skip check for pthread_t if NT-thread model is enabled
+  ac_cv_have_pthread_t=skip
+else
 AC_CACHE_CHECK([for pthread_t], [ac_cv_have_pthread_t], [
 AC_COMPILE_IFELSE([
   AC_LANG_PROGRAM([[@%:@include <pthread.h>]], [[pthread_t x; x = *(pthread_t*)0;]])
@@ -3147,7 +3346,7 @@ AS_VAR_IF([ac_cv_pthread_key_t_is_arithmetic_type], [yes], [
     AC_DEFINE([PTHREAD_KEY_T_IS_COMPATIBLE_WITH_INT], [1],
               [Define if pthread_key_t is compatible with int.])
 ])
-
+fi
 CC="$ac_save_cc"
 
 AC_MSG_CHECKING([for --enable-framework])
@@ -3302,6 +3501,9 @@ if test -z "$SHLIB_SUFFIX"; then
 	CYGWIN*)   SHLIB_SUFFIX=.dll;;
 	*)	   SHLIB_SUFFIX=.so;;
 	esac
+	case $host_os in
+	mingw*)    SHLIB_SUFFIX=.pyd;;
+	esac
 fi
 AC_MSG_RESULT([$SHLIB_SUFFIX])
 
@@ -3431,6 +3633,10 @@ then
 	CYGWIN*)
 		LDSHARED="gcc -shared -Wl,--enable-auto-image-base"
 		LDCXXSHARED="g++ -shared -Wl,--enable-auto-image-base";;
+  MINGW*)
+    LDSHARED='$(CC) -shared -Wl,--enable-auto-image-base'
+    LDCXXSHARED='$(CXX) -shared -Wl,--enable-auto-image-base'
+    ;;
 	*)	LDSHARED="ld";;
 	esac
 fi
@@ -3554,6 +3760,11 @@ then
 	VxWorks*)
 		LINKFORSHARED='-Wl,-export-dynamic';;
 	esac
+	case $host in
+	*-*-mingw*)
+		# for https://bugs.python.org/issue40458 on MINGW
+		LINKFORSHARED="-Wl,--stack,4194304";;
+	esac
 fi
 AC_MSG_RESULT([$LINKFORSHARED])
 
@@ -3618,7 +3829,12 @@ AC_SUBST([PERF_TRAMPOLINE_OBJ])
 
 # checks for libraries
 AC_CHECK_LIB([sendfile], [sendfile])
-AC_CHECK_LIB([dl], [dlopen])       # Dynamic linking for SunOS/Solaris and SYSV
+
+case $host in
+  *-*-mingw*) ;;
+  *) AC_CHECK_LIB([dl], [dlopen]) ;;	# Dynamic linking for SunOS/Solaris and SYSV
+esac
+
 AC_CHECK_LIB([dld], [shl_load])    # Dynamic linking for HP-UX
 
 
@@ -3679,16 +3895,30 @@ AS_VAR_IF([have_uuid], [missing], [
 
 AS_VAR_IF([have_uuid], [missing], [have_uuid=no])
 
+if test $with_nt_threads = yes ; then
+  dnl do not search for sem_init if NT-thread model is enabled
+  :
+else
 # 'Real Time' functions on Solaris
 # posix4 on Solaris 2.6
 # pthread (first!) on Linux
 AC_SEARCH_LIBS([sem_init], [pthread rt posix4])
+fi
 
 # check if we need libintl for locale functions
+case $host in
+  *-*-mingw*)
+  dnl Native windows build don't use libintl (see _localemodule.c).
+  dnl Also we don't like setup.py to add "intl" library to the list
+  dnl when build _locale module.
+  ;;
+  *)
 AC_CHECK_LIB([intl], [textdomain],
 	[AC_DEFINE([WITH_LIBINTL], [1],
 	[Define to 1 if libintl is needed for locale functions.])
         LIBS="-lintl $LIBS"])
+  ;;
+esac
 
 # checks for system dependent C++ extensions support
 case "$ac_sys_system" in
@@ -4054,6 +4284,36 @@ AS_CASE([$ac_sys_system],
   [OSSAUDIODEV_LIBS=""]
 )
 
+dnl On MINGW, you need to link against ws2_32 and iphlpapi for sockets to work
+AS_CASE([$MACHDEP],
+  [win32], [SOCKET_LIBS="-lws2_32 -liphlpapi -lrpcrt4"],
+  [SOCKET_LIBS=""]
+)
+
+dnl On MINGW, you need to link againt ws2_32 for _multiprocessing
+AS_CASE([$MACHDEP],
+  [win32], [MULTIPROCESSING_LIBS="-lws2_32"],
+  [MULTIPROCESSING_LIBS=""]
+)
+
+dnl On MINGW, you need to link againt ws2_32 for selectmodule
+AS_CASE([$MACHDEP],
+  [win32], [SELECTMODULE_LIBS="-lws2_32"],
+  [SELECTMODULE_LIBS=""]
+)
+
+dnl On MINGW, you need to link againt ole32, oleaut32 and uuid for ctypes
+AS_CASE([$MACHDEP],
+  [win32], [CTYPES_LIBS="-lole32 -loleaut32 -luuid"],
+  [CTYPES_LIBS=""]
+)
+
+dnl On MINGW, you need to link againt rpcrt4 for _uuid
+AS_CASE([$MACHDEP],
+  [win32], [UUID_LIBS="-lrpcrt4"],
+  [UUID_LIBS=""]
+)
+
 dnl detect sqlite3 from Emscripten emport
 PY_CHECK_EMSCRIPTEN_PORT([LIBSQLITE3], [-sUSE_SQLITE3])
 
@@ -4368,6 +4628,11 @@ done
 IFS=$as_save_IFS
 AC_MSG_RESULT([$DBM_CFLAGS $DBM_LIBS])
 
+case $host in
+  *-*-mingw*)
+    CFLAGS_NODIST="$CFLAGS_NODIST -D_WIN32_WINNT=0x0602";;
+esac
+
 # Templates for things AC_DEFINEd more than once.
 # For a single AC_DEFINE, no template is needed.
 AH_TEMPLATE([_REENTRANT],
@@ -4402,6 +4667,11 @@ then
         CXX="$CXX -pthread"
     fi
     posix_threads=yes
+elif test $with_nt_threads = yes
+then
+    posix_threads=no
+    AC_DEFINE(NT_THREADS, 1,
+        [Define to 1 if you want to use native NT threads])
 else
     if test ! -z "$withval" -a -d "$withval"
     then LDFLAGS="$LDFLAGS -L$withval"
@@ -4784,11 +5054,14 @@ AC_MSG_RESULT([$with_freelists])
 AC_MSG_CHECKING([for --with-c-locale-coercion])
 AC_ARG_WITH(
   [c-locale-coercion],
-  [AS_HELP_STRING([--with-c-locale-coercion], [enable C locale coercion to a UTF-8 based locale (default is yes)])])
+  [AS_HELP_STRING([--with-c-locale-coercion], [enable C locale coercion to a UTF-8 based locale (default is yes on Unix, no on Windows)])])
 
 if test -z "$with_c_locale_coercion"
 then
-    with_c_locale_coercion="yes"
+    case $host in
+      *-*-mingw*) with_c_locale_coercion="no";;
+      *) with_c_locale_coercion="yes";;
+    esac
 fi
 if test "$with_c_locale_coercion" != "no"
 then
@@ -4893,12 +5166,36 @@ then
 	fi
 	;;
 	esac
+	case $host in
+	*-*-mingw*)
+    DYNLOADFILE="dynload_win.o"
+    extra_machdep_objs="$extra_machdep_objs PC/dl_nt.o"
+    CFLAGS_NODIST="$CFLAGS_NODIST -DPY3_DLLNAME='L\"$DLLLIBRARY\"'"
+    case $host in
+        i686*)
+                CFLAGS_NODIST="$CFLAGS_NODIST -DMS_DLL_ID='\"${VERSION}-32\"'"
+            ;;
+        armv7*)
+                CFLAGS_NODIST="$CFLAGS_NODIST -DMS_DLL_ID='\"${VERSION}-arm32\"'"
+            ;;
+        aarch64*)
+                CFLAGS_NODIST="$CFLAGS_NODIST -DMS_DLL_ID='\"${VERSION}-arm64\"'"
+            ;;
+            *)
+                CFLAGS_NODIST="$CFLAGS_NODIST -DMS_DLL_ID='\"$VERSION\"'"
+            ;;
+      esac
+    ;;
+	esac
 fi
 AC_MSG_RESULT([$DYNLOADFILE])
 if test "$DYNLOADFILE" != "dynload_stub.o"
 then
+  have_dynamic_loading=yes
 	AC_DEFINE([HAVE_DYNAMIC_LOADING], [1],
         [Defined when any dynamic module loading is enabled.])
+else
+  have_dynamic_loading=no
 fi
 
 # MACHDEP_OBJS can be set to platform-specific object files needed by Python
@@ -4918,13 +5215,22 @@ else
 fi
 
 # checks for library functions
+if test $with_nt_threads = yes ; then
+  dnl GCC(mingw) 4.4+ require and use posix threads(pthreads-w32)
+  dnl and host may contain installed pthreads-w32.
+  dnl Skip checks for some functions declared in pthreads-w32 if
+  dnl NT-thread model is enabled.
+  ac_cv_func_pthread_kill=skip
+  ac_cv_func_sem_open=skip
+  ac_cv_func_sched_setscheduler=skip
+fi
 AC_CHECK_FUNCS([ \
   accept4 alarm bind_textdomain_codeset chmod chown clock close_range confstr \
   copy_file_range ctermid dup dup3 execv explicit_bzero explicit_memset \
   faccessat fchmod fchmodat fchown fchownat fdopendir fdwalk fexecve \
   fork fork1 fpathconf fstatat ftime ftruncate futimens futimes futimesat \
   gai_strerror getegid getentropy geteuid getgid getgrgid getgrgid_r \
-  getgrnam_r getgrouplist getgroups gethostname getitimer getloadavg getlogin \
+  getgrnam_r getgrouplist getgroups getitimer getloadavg getlogin \
   getpeername getpgid getpid getppid getpriority _getpty \
   getpwent getpwnam_r getpwuid getpwuid_r getresgid getresuid getrusage getsid getspent \
   getspnam getuid getwd if_nameindex initgroups kill killpg lchown linkat \
@@ -4937,7 +5243,7 @@ AC_CHECK_FUNCS([ \
   sched_setparam sched_setscheduler sem_clockwait sem_getvalue sem_open \
   sem_timedwait sem_unlink sendfile setegid seteuid setgid sethostname \
   setitimer setlocale setpgid setpgrp setpriority setregid setresgid \
-  setresuid setreuid setsid setuid setvbuf shutdown sigaction sigaltstack \
+  setresuid setreuid setsid setuid setvbuf sigaction sigaltstack \
   sigfillset siginterrupt sigpending sigrelse sigtimedwait sigwait \
   sigwaitinfo snprintf splice strftime strlcpy strsignal symlinkat sync \
   sysconf system tcgetpgrp tcsetpgrp tempnam timegm times tmpfile \
@@ -5151,7 +5457,13 @@ PKG_CHECK_MODULES([LIBLZMA], [liblzma], [have_liblzma=yes], [
 ])
 
 dnl PY_CHECK_NETDB_FUNC(FUNCTION)
-AC_DEFUN([PY_CHECK_NETDB_FUNC], [PY_CHECK_FUNC([$1], [@%:@include <netdb.h>])])
+AC_DEFUN([PY_CHECK_NETDB_FUNC], [PY_CHECK_FUNC([$1], [
+#ifdef _WIN32
+  #include <winsock.h>
+#else
+  #include <netdb.h>
+#endif
+])])
 
 PY_CHECK_NETDB_FUNC([hstrerror])
 dnl not available in WASI yet
@@ -5160,13 +5472,19 @@ PY_CHECK_NETDB_FUNC([getservbyport])
 PY_CHECK_NETDB_FUNC([gethostbyname])
 PY_CHECK_NETDB_FUNC([gethostbyaddr])
 PY_CHECK_NETDB_FUNC([getprotobyname])
+PY_CHECK_NETDB_FUNC([gethostname])
+PY_CHECK_NETDB_FUNC([shutdown])
 
 dnl PY_CHECK_SOCKET_FUNC(FUNCTION)
 AC_DEFUN([PY_CHECK_SOCKET_FUNC], [PY_CHECK_FUNC([$1], [
+#ifdef _WIN32
+#include <ws2tcpip.h>
+#else
 #include <sys/types.h>
 #include <sys/socket.h>
 #include <netinet/in.h>
 #include <arpa/inet.h>
+#endif
 ])])
 
 PY_CHECK_SOCKET_FUNC([inet_aton])
@@ -5274,6 +5592,9 @@ WITH_SAVE_ENV([
   ])
 ])
 
+case $host in
+  *-*-mingw*) ;;
+  *)
 AC_CHECK_FUNCS([clock_gettime], [], [
     AC_CHECK_LIB([rt], [clock_gettime], [
         LIBS="$LIBS -lrt"
@@ -5294,6 +5615,8 @@ AC_CHECK_FUNCS([clock_settime], [], [
         AC_DEFINE([HAVE_CLOCK_SETTIME], [1])
     ])
 ])
+  ;;
+esac
 
 AC_CHECK_FUNCS([clock_nanosleep], [], [
     AC_CHECK_LIB([rt], [clock_nanosleep], [
@@ -5489,18 +5812,33 @@ if test $ac_cv_header_time_altzone = yes; then
     [Define this if your time.h defines altzone.])
 fi
 
+AC_CHECK_HEADERS([ws2tcpip.h])
 AC_CACHE_CHECK([for addrinfo], [ac_cv_struct_addrinfo],
-AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[@%:@include <netdb.h>]], [[struct addrinfo a]])],
+AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
+#ifdef HAVE_WS2TCPIP_H
+#  include <ws2tcpip.h>
+#else
+#  include <netdb.h>
+#endif]],
+    [[struct addrinfo a]])],
   [ac_cv_struct_addrinfo=yes],
   [ac_cv_struct_addrinfo=no]))
 if test $ac_cv_struct_addrinfo = yes; then
-	AC_DEFINE([HAVE_ADDRINFO], [1], [struct addrinfo (netdb.h)])
+	AC_DEFINE([HAVE_ADDRINFO], [1], [struct addrinfo])
 fi
 
 AC_CACHE_CHECK([for sockaddr_storage], [ac_cv_struct_sockaddr_storage],
 AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
-#		include <sys/types.h>
-@%:@		include <sys/socket.h>]], [[struct sockaddr_storage s]])],
+#ifdef HAVE_WS2TCPIP_H
+#include <ws2tcpip.h>
+#endif
+#ifdef HAVE_SYS_TYPES_H
+#include <sys/types.h>
+#endif
+#ifdef HAVE_SYS_SOCKET_H
+#include <sys/socket.h>
+#endif]],
+    [[struct sockaddr_storage s]])],
   [ac_cv_struct_sockaddr_storage=yes],
   [ac_cv_struct_sockaddr_storage=no]))
 if test $ac_cv_struct_sockaddr_storage = yes; then
@@ -5814,6 +6152,10 @@ dnl actually works.  For FreeBSD versions <= 7.2,
 dnl the kernel module that provides POSIX semaphores
 dnl isn't loaded by default, so an attempt to call
 dnl sem_open results in a 'Signal 12' error.
+if test $with_nt_threads = yes ; then
+  dnl skip posix semaphores test if NT-thread model is enabled
+  ac_cv_posix_semaphores_enabled=no
+fi
 AC_CACHE_CHECK([whether POSIX semaphores are enabled], [ac_cv_posix_semaphores_enabled],
   AC_RUN_IFELSE([
     AC_LANG_SOURCE([
@@ -5847,6 +6189,14 @@ AS_VAR_IF([ac_cv_posix_semaphores_enabled], [no], [
 ])
 
 dnl Multiprocessing check for broken sem_getvalue
+if test $with_nt_threads = yes ; then
+  dnl Skip test if NT-thread model is enabled.
+  dnl NOTE the test case below fail for pthreads-w32 as:
+  dnl - SEM_FAILED is not defined;
+  dnl - sem_open is a stub;
+  dnl - sem_getvalue work(!).
+  ac_cv_broken_sem_getvalue=skip
+fi
 AC_CACHE_CHECK([for broken sem_getvalue], [ac_cv_broken_sem_getvalue],
   AC_RUN_IFELSE([
     AC_LANG_SOURCE([
@@ -5883,7 +6233,10 @@ AS_VAR_IF([ac_cv_broken_sem_getvalue], [yes], [
   )
 ])
 
-AC_CHECK_DECLS([RTLD_LAZY, RTLD_NOW, RTLD_GLOBAL, RTLD_LOCAL, RTLD_NODELETE, RTLD_NOLOAD, RTLD_DEEPBIND, RTLD_MEMBER], [], [], [[@%:@include <dlfcn.h>]])
+case $host in
+  *-*-mingw*) ;;
+  *) AC_CHECK_DECLS([RTLD_LAZY, RTLD_NOW, RTLD_GLOBAL, RTLD_LOCAL, RTLD_NODELETE, RTLD_NOLOAD, RTLD_DEEPBIND, RTLD_MEMBER], [], [], [[@%:@include <dlfcn.h>]])
+esac
 
 # determine what size digit to use for Python's longs
 AC_MSG_CHECKING([digit size for Python's longs])
@@ -5973,6 +6326,61 @@ esac
 # check for endianness
 AC_C_BIGENDIAN
 
+AC_SUBST(PYD_PLATFORM_TAG)
+# Special case of PYD_PLATFORM_TAG with python build with mingw. 
+# Python can with different cpu arch and c runtime as well as different
+# toolchain. We follow this`mingw_<cpu_arch>_<c_runtime>_<toolchain>`
+# convention for PYD_PLATFORM_TAG. Where:
+# `cpu_arch` = `x86_64`, `aarch64` or `i686`
+# `c_runtime` = `msvcrt` or `ucrt`
+# `toolchain` = `gnu` or `llvm`
+PYD_PLATFORM_TAG=""
+case $host in
+  *-*-mingw*)
+    # check if we are linking to ucrt
+    AC_MSG_CHECKING(whether linking to ucrt)
+    AC_COMPILE_IFELSE([AC_LANG_SOURCE([[
+    #include <stdio.h>
+    #ifndef _UCRT
+        #error no ucrt
+    #endif
+    int main(){ return 0; }
+    ]])],[linking_to_ucrt=yes],[linking_to_ucrt=no])
+    AC_MSG_RESULT($linking_to_ucrt)
+    ;;
+esac
+case $host_os in
+    mingw*)
+  AC_MSG_CHECKING(PYD_PLATFORM_TAG)
+  PYD_PLATFORM_TAG="mingw"
+  case $host in
+  i686-*-mingw*)
+    PYD_PLATFORM_TAG+="_i686"
+    ;;
+  x86_64-*-mingw*)
+    PYD_PLATFORM_TAG+="_x86_64"
+    ;;
+  aarch64-*-mingw*)
+    PYD_PLATFORM_TAG+="_aarch64"
+    ;;
+  armv7-*-mingw*)
+    PYD_PLATFORM_TAG+="_armv7"
+    ;;
+  esac
+  if test $linking_to_ucrt = no; then
+    PYD_PLATFORM_TAG+="_msvcrt"
+  else
+    PYD_PLATFORM_TAG+="_ucrt"
+  fi
+  if test -n "${cc_is_clang}"; then
+    # it is CLANG32
+    PYD_PLATFORM_TAG+="_llvm"
+  else
+    PYD_PLATFORM_TAG+="_gnu"
+  fi
+  AC_MSG_RESULT($PYD_PLATFORM_TAG)
+esac
+
 # ABI version string for Python extension modules.  This appears between the
 # periods in shared library file names, e.g. foo.<SOABI>.so.  It is calculated
 # from the following attributes which affect the ABI of this Python build (in
@@ -6005,7 +6413,12 @@ if test "$Py_DEBUG" = 'true' -a "$with_trace_refs" != "yes"; then
 fi
 
 AC_SUBST([EXT_SUFFIX])
-EXT_SUFFIX=.${SOABI}${SHLIB_SUFFIX}
+VERSION_NO_DOTS=$(echo $LDVERSION | tr -d .)
+if test -n "${PYD_PLATFORM_TAG}"; then
+  EXT_SUFFIX=".cp${VERSION_NO_DOTS}-${PYD_PLATFORM_TAG}${SHLIB_SUFFIX}"
+else
+  EXT_SUFFIX=.${SOABI}${SHLIB_SUFFIX}
+fi
 
 AC_MSG_CHECKING([LDVERSION])
 LDVERSION='$(VERSION)$(ABIFLAGS)'
@@ -6013,7 +6426,7 @@ AC_MSG_RESULT([$LDVERSION])
 
 # On Android and Cygwin the shared libraries must be linked with libpython.
 AC_SUBST([LIBPYTHON])
-if test "$PY_ENABLE_SHARED" = "1" && ( test -n "$ANDROID_API_LEVEL" || test "$MACHDEP" = "cygwin"); then
+if test "$PY_ENABLE_SHARED" = "1" && ( test -n "$ANDROID_API_LEVEL" || test "$MACHDEP" = "cygwin" || test "$MACHDEP" = "win32"); then
   LIBPYTHON="-lpython${VERSION}${ABIFLAGS}"
 else
   LIBPYTHON=''
@@ -6446,6 +6859,14 @@ dnl have_panel=[no, panelw, panel]
 have_curses=no
 have_panel=no
 
+case "$host_os" in
+	mingw*)
+	# On Mingw, include directory is different, so just assume
+  # it's there.
+	ac_cv_header_ncurses_h=yes
+	;;
+esac
+
 AH_TEMPLATE([HAVE_NCURSESW], [Define to 1 if you have the `ncursesw' library.])
 AC_CHECK_HEADERS([curses.h ncurses.h])
 
@@ -6557,11 +6978,16 @@ AS_VAR_IF([have_panel], [no], [
   AC_MSG_RESULT([$have_panel (CFLAGS: $PANEL_CFLAGS, LIBS: $PANEL_LIBS)])
 ])
 
+if test -n "$PKG_CONFIG"; then
+    NCURSESW_INCLUDEDIR="`"$PKG_CONFIG" ncursesw --cflags-only-I 2>/dev/null | sed -e 's/^-I//;s/ .*$//'`"
+else
+    NCURSESW_INCLUDEDIR=""
+fi
+AC_SUBST(NCURSESW_INCLUDEDIR)
+
 # first curses header check
 ac_save_cppflags="$CPPFLAGS"
-if test "$cross_compiling" = no; then
-  CPPFLAGS="$CPPFLAGS -I/usr/include/ncursesw"
-fi
+CPPFLAGS="$CPPFLAGS -I$NCURSESW_INCLUDEDIR"
 
 # On Solaris, term.h requires curses.h
 AC_CHECK_HEADERS([term.h], [], [], [
@@ -6681,8 +7107,11 @@ AC_CHECK_TYPE(
   [socklen_t], [],
   [AC_DEFINE(
     [socklen_t], [int],
-    [Define to `int' if <sys/socket.h> does not define.]
+    [Define to `int' if <sys/socket.h> or <ws2tcpip.h> does not define.]
   )], [
+#ifdef HAVE_WS2TCPIP_H
+#include <ws2tcpip.h>
+#endif
 #ifdef HAVE_SYS_TYPES_H
 #include <sys/types.h>
 #endif
@@ -6776,6 +7205,27 @@ do
   THREADHEADERS="$THREADHEADERS \$(srcdir)/$h"
 done
 
+case $host in
+  *-*-mingw*)
+    dnl Required for windows builds as Objects/exceptions.c require
+    dnl "errmap.h" from $srcdir/PC.
+    dnl Note we cannot use BASECPPFLAGS as autogenerated pyconfig.h
+    dnl has to be before customized located in ../PC.
+    dnl (-I. at end is workaround for setup.py logic)
+    CPPFLAGS="-I\$(srcdir)/PC $CPPFLAGS -I."
+    ;;
+esac
+
+dnl Python interpreter main program for frozen scripts
+AC_SUBST(PYTHON_OBJS_FROZENMAIN)
+PYTHON_OBJS_FROZENMAIN="Python/frozenmain.o"
+case $host in
+  *-*-mingw*)
+    dnl 'PC/frozen_dllmain.c' - not yet
+    PYTHON_OBJS_FROZENMAIN=
+    ;;
+esac
+
 AC_SUBST([SRCDIRS])
 SRCDIRS="\
   Modules \
@@ -6798,6 +7248,11 @@ SRCDIRS="\
   Python \
   Python/frozen_modules \
   Python/deepfreeze"
+
+case $host in
+  *-*-mingw*) SRCDIRS="$SRCDIRS PC";;
+esac
+
 AC_MSG_CHECKING([for build directories])
 for dir in $SRCDIRS; do
     if test ! -d $dir; then
@@ -6806,6 +7261,38 @@ for dir in $SRCDIRS; do
 done
 AC_MSG_RESULT([done])
 
+# For mingw build need additional library for linking
+case $host in
+  *-*-mingw*)
+    LIBS="$LIBS -lversion -lshlwapi -lpathcch -lbcrypt"
+    AC_PROG_AWK
+    if test "$AWK" = "gawk"; then
+      awk_extra_flag="--non-decimal-data"
+    fi
+    AC_MSG_CHECKING([FIELD3])
+    FIELD3=$($AWK $awk_extra_flag '\
+      /^#define PY_RELEASE_LEVEL_/             {levels[$2]=$3}    \
+      /^#define PY_MICRO_VERSION[[:space:]]+/  {micro=$3}         \
+      /^#define PY_RELEASE_LEVEL[[:space:]]+/  {level=levels[$3]} \
+      /^#define PY_RELEASE_SERIAL[[:space:]]+/ {serial=$3}        \
+      END {print micro * 1000 + level * 10 + serial}' \
+      $srcdir/Include/patchlevel.h
+    )
+    
+    AC_MSG_RESULT([${FIELD3}])
+    RCFLAGS="$RCFLAGS -DFIELD3=$FIELD3 -O COFF"
+
+    case $host in
+      i686*)  RCFLAGS="$RCFLAGS --target=pe-i386" ;;
+      x86_64*)  RCFLAGS="$RCFLAGS --target=pe-x86-64" ;;
+      *) ;;
+    esac
+  ;;
+  *)
+  ;;
+esac
+AC_SUBST(RCFLAGS)
+
 # Availability of -O2:
 AC_CACHE_CHECK([for -O2], [ac_cv_compile_o2], [
 saved_cflags="$CFLAGS"
@@ -7284,6 +7771,7 @@ AS_CASE([$ac_sys_system],
   [VxWorks*], [PY_STDLIB_MOD_SET_NA([_scproxy], [_crypt], [termios], [grp])],
   [Darwin], [PY_STDLIB_MOD_SET_NA([ossaudiodev], [spwd])],
   [CYGWIN*], [PY_STDLIB_MOD_SET_NA([_scproxy], [nis])],
+  [MINGW*], [PY_STDLIB_MOD_SET_NA([readline])],
   [QNX*], [PY_STDLIB_MOD_SET_NA([_scproxy], [nis])],
   [FreeBSD*], [PY_STDLIB_MOD_SET_NA([_scproxy], [spwd])],
   [Emscripten|WASI], [
@@ -7423,10 +7911,9 @@ PY_STDLIB_MOD_SIMPLE([_json])
 PY_STDLIB_MOD_SIMPLE([_lsprof])
 PY_STDLIB_MOD_SIMPLE([_opcode])
 PY_STDLIB_MOD_SIMPLE([_pickle])
-PY_STDLIB_MOD_SIMPLE([_posixsubprocess])
 PY_STDLIB_MOD_SIMPLE([_queue])
 PY_STDLIB_MOD_SIMPLE([_random])
-PY_STDLIB_MOD_SIMPLE([select])
+PY_STDLIB_MOD_SIMPLE([select], [], [$SELECTMODULE_LIBS])
 PY_STDLIB_MOD_SIMPLE([_struct])
 PY_STDLIB_MOD_SIMPLE([_typing])
 PY_STDLIB_MOD_SIMPLE([_xxsubinterpreters])
@@ -7435,8 +7922,8 @@ PY_STDLIB_MOD_SIMPLE([_zoneinfo])
 
 dnl multiprocessing modules
 PY_STDLIB_MOD([_multiprocessing],
-  [], [test "$ac_cv_func_sem_unlink" = "yes"],
-  [-I\$(srcdir)/Modules/_multiprocessing])
+  [], [test "$ac_cv_func_sem_unlink" = "yes" -o "$MACHDEP" = "win32"],
+  [-I\$(srcdir)/Modules/_multiprocessing], [$MULTIPROCESSING_LIBS])
 PY_STDLIB_MOD([_posixshmem],
   [], [test "$have_posix_shmem" = "yes"],
   [$POSIXSHMEM_CFLAGS], [$POSIXSHMEM_LIBS])
@@ -7455,11 +7942,15 @@ PY_STDLIB_MOD([fcntl],
   [], [test "$ac_cv_header_sys_ioctl_h" = "yes" -a "$ac_cv_header_fcntl_h" = "yes"],
   [], [$FCNTL_LIBS])
 PY_STDLIB_MOD([mmap],
-  [], [test "$ac_cv_header_sys_mman_h" = "yes" -a "$ac_cv_header_sys_stat_h" = "yes"])
+  [], m4_flatten([test "$ac_cv_header_sys_mman_h" = "yes"
+                    -a "$ac_cv_header_sys_stat_h" = "yes"
+                    -o "$MACHDEP" = "win32"]))
 PY_STDLIB_MOD([_socket],
   [], m4_flatten([test "$ac_cv_header_sys_socket_h" = "yes"
                     -a "$ac_cv_header_sys_types_h" = "yes"
-                    -a "$ac_cv_header_netinet_in_h" = "yes"]))
+                    -a "$ac_cv_header_netinet_in_h" = "yes"
+                    -o "$MACHDEP" = "win32"]),
+  [], [$SOCKET_LIBS])
 
 dnl platform specific extensions
 PY_STDLIB_MOD([grp], [], [test "$ac_cv_func_getgrgid" = yes -o "$ac_cv_func_getgrgid_r" = yes])
@@ -7474,6 +7965,7 @@ PY_STDLIB_MOD([_scproxy],
 PY_STDLIB_MOD([spwd], [], [test "$ac_cv_func_getspent" = yes -o "$ac_cv_func_getspnam" = yes])
 PY_STDLIB_MOD([syslog], [], [test "$ac_cv_header_syslog_h" = yes])
 PY_STDLIB_MOD([termios], [], [test "$ac_cv_header_termios_h" = yes])
+PY_STDLIB_MOD([_posixsubprocess], [], [test "$MACHDEP" != "win32"])
 
 dnl _elementtree loads libexpat via CAPI hook in pyexpat
 PY_STDLIB_MOD([pyexpat],
@@ -7510,7 +8002,7 @@ PY_STDLIB_MOD([_crypt],
   [$LIBCRYPT_CFLAGS], [$LIBCRYPT_LIBS])
 PY_STDLIB_MOD([_ctypes],
   [], [test "$have_libffi" = yes],
-  [$NO_STRICT_OVERFLOW_CFLAGS $LIBFFI_CFLAGS], [$LIBFFI_LIBS])
+  [$NO_STRICT_OVERFLOW_CFLAGS $LIBFFI_CFLAGS], [$LIBFFI_LIBS $CTYPES_LIBS])
 PY_STDLIB_MOD([_curses],
   [], [test "$have_curses" != "no"],
   [$CURSES_CFLAGS], [$CURSES_LIBS]
@@ -7540,8 +8032,8 @@ PY_STDLIB_MOD([_tkinter],
   [], [test "$have_tcltk" = "yes"],
   [$TCLTK_CFLAGS], [$TCLTK_LIBS])
 PY_STDLIB_MOD([_uuid],
-  [], [test "$have_uuid" = "yes"],
-  [$LIBUUID_CFLAGS], [$LIBUUID_LIBS])
+  [], [test "$have_uuid" = "yes" -o "$MACHDEP" = "win32"],
+  [$LIBUUID_CFLAGS], [$LIBUUID_LIBS $UUID_LIBS])
 
 dnl compression libs
 PY_STDLIB_MOD([zlib], [], [test "$have_zlib" = yes],
@@ -7555,28 +8047,40 @@ PY_STDLIB_MOD([_lzma], [], [test "$have_liblzma" = yes],
 
 dnl OpenSSL bindings
 PY_STDLIB_MOD([_ssl], [], [test "$ac_cv_working_openssl_ssl" = yes],
-  [$OPENSSL_INCLUDES], [$OPENSSL_LDFLAGS $OPENSSL_LDFLAGS_RPATH $OPENSSL_LIBS])
+  [$OPENSSL_INCLUDES], [$OPENSSL_LDFLAGS $OPENSSL_LDFLAGS_RPATH $OPENSSL_LIBS -lws2_32])
 PY_STDLIB_MOD([_hashlib], [], [test "$ac_cv_working_openssl_hashlib" = yes],
   [$OPENSSL_INCLUDES], [$OPENSSL_LDFLAGS $OPENSSL_LDFLAGS_RPATH $LIBCRYPTO_LIBS])
 
+dnl windows specific modules
+PY_STDLIB_MOD([winreg], [test "$MACHDEP" = "win32"])
+PY_STDLIB_MOD([msvcrt], [test "$MACHDEP" = "win32"])
+PY_STDLIB_MOD([_winapi], [test "$MACHDEP" = "win32"])
+PY_STDLIB_MOD([_msi], [test "$MACHDEP" = "win32"], [], [],
+  [-lmsi -lcabinet -lrpcrt4])
+PY_STDLIB_MOD([winsound], [test "$MACHDEP" = "win32"], [], [],
+  [-lwinmm])
+PY_STDLIB_MOD([_overlapped], [test "$MACHDEP" = "win32"], [], [],
+  [-lws2_32])
+
 dnl test modules
 PY_STDLIB_MOD([_testcapi], [test "$TEST_MODULES" = yes])
 PY_STDLIB_MOD([_testclinic], [test "$TEST_MODULES" = yes])
-PY_STDLIB_MOD([_testinternalcapi], [test "$TEST_MODULES" = yes])
+PY_STDLIB_MOD([_testinternalcapi], [test "$TEST_MODULES" = yes], [], [-DPY3_DLLNAME="\"$DLLLIBRARY\""], [])
 PY_STDLIB_MOD([_testbuffer], [test "$TEST_MODULES" = yes])
-PY_STDLIB_MOD([_testimportmultiple], [test "$TEST_MODULES" = yes], [test "$ac_cv_func_dlopen" = yes])
-PY_STDLIB_MOD([_testmultiphase], [test "$TEST_MODULES" = yes], [test "$ac_cv_func_dlopen" = yes])
+PY_STDLIB_MOD([_testimportmultiple], [test "$TEST_MODULES" = yes], [test "$have_dynamic_loading" = yes])
+PY_STDLIB_MOD([_testmultiphase], [test "$TEST_MODULES" = yes], [test "$have_dynamic_loading" = yes])
 PY_STDLIB_MOD([xxsubtype], [test "$TEST_MODULES" = yes])
 PY_STDLIB_MOD([_xxtestfuzz], [test "$TEST_MODULES" = yes])
+PY_STDLIB_MOD([_testconsole], [test "$TEST_MODULES" = yes -a "$MACHDEP" = "win32"])
 PY_STDLIB_MOD([_ctypes_test],
-  [test "$TEST_MODULES" = yes], [test "$have_libffi" = yes -a "$ac_cv_func_dlopen" = yes],
-  [], [$LIBM])
+  [test "$TEST_MODULES" = yes], [test "$have_libffi" = yes -a "$have_dynamic_loading" = yes],
+  [], [$LIBM $CTYPES_LIBS])
 
 dnl Limited API template modules.
 dnl The limited C API is not compatible with the Py_TRACE_REFS macro.
 dnl Emscripten does not support shared libraries yet.
-PY_STDLIB_MOD([xxlimited], [test "$with_trace_refs" = "no"], [test "$ac_cv_func_dlopen" = yes])
-PY_STDLIB_MOD([xxlimited_35], [test "$with_trace_refs" = "no"], [test "$ac_cv_func_dlopen" = yes])
+PY_STDLIB_MOD([xxlimited], [test "$with_trace_refs" = "no"], [test "$have_dynamic_loading" = yes])
+PY_STDLIB_MOD([xxlimited_35], [test "$with_trace_refs" = "no"], [test "$have_dynamic_loading" = yes])
 
 # substitute multiline block, must come after last PY_STDLIB_MOD()
 AC_SUBST([MODULE_BLOCK])
diff --git a/mingw_ignorefile.txt b/mingw_ignorefile.txt
new file mode 100644
index 00000000000000..550e72413a4f4e
--- /dev/null
+++ b/mingw_ignorefile.txt
@@ -0,0 +1,25 @@
+test.test_ctypes.test_loading.LoaderTest.test_load_dll_with_flags
+distutils.tests.test_bdist_dumb.BuildDumbTestCase.test_simple_built
+distutils.tests.test_cygwinccompiler.CygwinCCompilerTestCase.test_get_versions
+distutils.tests.test_util.UtilTestCase.test_change_root
+test.test_compileall.CommandLineTestsNoSourceEpoch.*
+test.test_compileall.CommandLineTestsWithSourceEpoch.*
+test.test_compileall.CompileallTestsWithoutSourceEpoch.*
+test.test_compileall.CompileallTestsWithSourceEpoch.*
+test.test_import.ImportTests.test_dll_dependency_import
+test.test_ntpath.NtCommonTest.test_import
+test.test_os.StatAttributeTests.test_stat_block_device
+test.test_os.TestScandir.test_attributes
+test.test_os.UtimeTests.test_large_time
+test.test_platform.PlatformTest.test_architecture_via_symlink
+test.test_regrtest.ProgramsTestCase.test_pcbuild_rt
+test.test_regrtest.ProgramsTestCase.test_tools_buildbot_test
+test.test_site._pthFileTests.*
+test.test_site.HelperFunctionsTests.*
+test.test_site.StartupImportTests.*
+test.test_ssl.*
+test.test_venv.BasicTest.*
+test.test_venv.EnsurePipTest.*
+
+test.test_dict.DictTest.test_splittable_to_generic_combinedtable
+test.test_capi.test_run.CAPITest.test_run_fileexflags
diff --git a/mingw_ignorefile_msvcrt.txt b/mingw_ignorefile_msvcrt.txt
new file mode 100644
index 00000000000000..be363bd0faf404
--- /dev/null
+++ b/mingw_ignorefile_msvcrt.txt
@@ -0,0 +1,8 @@
+test.datetimetester.TestLocalTimeDisambiguation_Fast.*
+test.datetimetester.TestLocalTimeDisambiguation_Pure.*
+test.test_cmath.CMathTests.test_specific_values
+test.test_math.MathTests.*
+test.test_strptime.CalculationTests.*
+test.test_strptime.StrptimeTests.test_weekday
+test.test_strptime.TimeRETests.test_compile
+test.test_tools.test_i18n.Test_pygettext.test_POT_Creation_Date
diff --git a/mingw_smoketests.py b/mingw_smoketests.py
new file mode 100644
index 00000000000000..5af27645e5df7e
--- /dev/null
+++ b/mingw_smoketests.py
@@ -0,0 +1,371 @@
+#!/usr/bin/env python3
+# Copyright 2017 Christoph Reiter
+#
+# Permission is hereby granted, free of charge, to any person obtaining
+# a copy of this software and associated documentation files (the
+# "Software"), to deal in the Software without restriction, including
+# without limitation the rights to use, copy, modify, merge, publish,
+# distribute, sublicense, and/or sell copies of the Software, and to
+# permit persons to whom the Software is furnished to do so, subject to
+# the following conditions:
+#
+# The above copyright notice and this permission notice shall be included
+# in all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+# IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+# CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+# TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+# SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+"""The goal of this test suite is collect tests for update regressions
+and to test msys2 related modifications like for path handling.
+Feel free to extend.
+"""
+
+import os
+import unittest
+import sysconfig
+
+if os.environ.get("MSYSTEM", ""):
+    SEP = "/"
+else:
+    SEP = "\\"
+
+if sysconfig.is_python_build():
+    os.environ["PYTHONLEGACYWINDOWSDLLLOADING"] = "1"
+
+_UCRT = 'ucrt' in sysconfig.get_platform()
+
+
+class Tests(unittest.TestCase):
+
+    def test_zoneinfo(self):
+        # https://github.com/msys2-contrib/cpython-mingw/issues/32
+        import zoneinfo
+        self.assertTrue(any(os.path.exists(p) for p in zoneinfo.TZPATH))
+        zoneinfo.ZoneInfo("America/Sao_Paulo")
+
+    def test_userdir_path_sep(self):
+        # Make sure os.path and pathlib use the same path separators
+        from unittest import mock
+        from os.path import expanduser
+        from pathlib import Path
+
+        profiles = ["C:\\foo", "C:/foo"]
+        for profile in profiles:
+            with mock.patch.dict(os.environ, {"USERPROFILE": profile}):
+                self.assertEqual(expanduser("~"), os.path.normpath(expanduser("~")))
+                self.assertEqual(str(Path("~").expanduser()), expanduser("~"))
+                self.assertEqual(str(Path.home()), expanduser("~"))
+
+    # def test_sysconfig_schemes(self):
+    #     # https://github.com/msys2/MINGW-packages/issues/9319
+    #     import sysconfig
+    #     from distutils.dist import Distribution
+    #     from distutils.command.install import install
+
+    #     names = ['scripts', 'purelib', 'platlib', 'data', 'include']
+    #     for scheme in ["nt", "nt_user"]:
+    #         for name in names:
+    #             c = install(Distribution({"name": "foobar"}))
+    #             c.user = (scheme == "nt_user")
+    #             c.finalize_options()
+    #             if name == "include":
+    #                 dist_path = os.path.dirname(getattr(c, "install_" + "headers"))
+    #             else:
+    #                 dist_path = getattr(c, "install_" + name)
+    #             sys_path = sysconfig.get_path(name, scheme)
+    #             self.assertEqual(dist_path, sys_path, (scheme, name))
+
+    def test_ctypes_find_library(self):
+        from ctypes.util import find_library
+        from ctypes import cdll
+        self.assertTrue(cdll.msvcrt)
+        if _UCRT:
+            self.assertIsNone(find_library('c'))
+        else:
+            self.assertEqual(find_library('c'), 'msvcrt.dll')
+
+    def test_ctypes_dlopen(self):
+        import ctypes
+        import sys
+        self.assertEqual(ctypes.RTLD_GLOBAL, 0)
+        self.assertEqual(ctypes.RTLD_GLOBAL,  ctypes.RTLD_LOCAL)
+        self.assertFalse(hasattr(sys, 'setdlopenflags'))
+        self.assertFalse(hasattr(sys, 'getdlopenflags'))
+        self.assertFalse([n for n in dir(os) if n.startswith("RTLD_")])
+
+    def test_time_no_unix_stuff(self):
+        import time
+        self.assertFalse([n for n in dir(time) if n.startswith("clock_")])
+        self.assertFalse([n for n in dir(time) if n.startswith("CLOCK_")])
+        self.assertFalse([n for n in dir(time) if n.startswith("pthread_")])
+        self.assertFalse(hasattr(time, 'tzset'))
+
+    def test_strftime(self):
+        import time
+        with self.assertRaises(ValueError):
+            time.strftime('%Y', (12345,) + (0,) * 8)
+
+    def test_sep(self):
+        self.assertEqual(os.sep, SEP)
+
+    def test_module_file_path(self):
+        import asyncio
+        import zlib
+        self.assertEqual(zlib.__file__, os.path.normpath(zlib.__file__))
+        self.assertEqual(asyncio.__file__, os.path.normpath(asyncio.__file__))
+
+    def test_importlib_frozen_path_sep(self):
+        import importlib._bootstrap_external
+        self.assertEqual(importlib._bootstrap_external.path_sep, SEP)
+
+    def test_os_commonpath(self):
+        self.assertEqual(
+            os.path.commonpath(
+                [os.path.join("C:", os.sep, "foo", "bar"),
+                 os.path.join("C:", os.sep, "foo")]),
+                 os.path.join("C:", os.sep, "foo"))
+
+    def test_pathlib(self):
+        import pathlib
+
+        p = pathlib.Path("foo") / pathlib.Path("foo")
+        self.assertEqual(str(p), os.path.normpath(p))
+
+    def test_modules_import(self):
+        import sqlite3
+        import ssl
+        import ctypes
+        import curses
+
+    def test_c_modules_import(self):
+        import _decimal
+
+    def test_socket_inet_ntop(self):
+        import socket
+        self.assertTrue(hasattr(socket, "inet_ntop"))
+
+    def test_socket_inet_pton(self):
+        import socket
+        self.assertTrue(hasattr(socket, "inet_pton"))
+
+    def test_multiprocessing_queue(self):
+        from multiprocessing import Queue
+        Queue(0)
+
+    #def test_socket_timout_normal_error(self):
+    #    import urllib.request
+    #    from urllib.error import URLError
+
+    #    try:
+    #        urllib.request.urlopen(
+    #            'http://localhost', timeout=0.0001).close()
+    #    except URLError:
+    #        pass
+
+    def test_threads(self):
+        from concurrent.futures import ThreadPoolExecutor
+
+        with ThreadPoolExecutor(1) as pool:
+            for res in pool.map(lambda *x: None, range(10000)):
+                pass
+
+    def test_sysconfig(self):
+        import sysconfig
+        # This should be able to execute without exceptions
+        sysconfig.get_config_vars()
+
+    def test_sqlite_enable_load_extension(self):
+        # Make sure --enable-loadable-sqlite-extensions is used
+        import sqlite3
+        self.assertTrue(sqlite3.Connection.enable_load_extension)
+
+    def test_venv_creation(self):
+        import tempfile
+        import venv
+        import subprocess
+        import shutil
+        with tempfile.TemporaryDirectory() as tmp:
+            builder = venv.EnvBuilder()
+            builder.create(tmp)
+            assert os.path.exists(os.path.join(tmp, "bin", "activate"))
+            assert os.path.exists(os.path.join(tmp, "bin", "python.exe"))
+            assert os.path.exists(os.path.join(tmp, "bin", "python3.exe"))
+            subprocess.check_call([shutil.which("bash.exe"), os.path.join(tmp, "bin", "activate")])
+
+            # This will not work in in-tree build
+            if not sysconfig.is_python_build():
+                op = subprocess.check_output(
+                    [
+                        os.path.join(tmp, "bin", "python.exe"),
+                        "-c",
+                        "print('Hello World')"
+                    ],
+                    cwd=tmp,
+                )
+                assert op.decode().strip() == "Hello World"
+
+    def test_has_mktime(self):
+        from time import mktime, gmtime
+        mktime(gmtime())
+
+    def test_platform_things(self):
+        import sys
+        import sysconfig
+        import platform
+        import importlib.machinery
+        import tempfile
+        import venv
+        import subprocess
+        self.assertEqual(sys.implementation.name, "cpython")
+        self.assertEqual(sys.platform, "win32")
+        self.assertTrue(sysconfig.get_platform().startswith("mingw"))
+        self.assertTrue(sysconfig.get_config_var('SOABI').startswith("cpython-"))
+        ext_suffix = sysconfig.get_config_var('EXT_SUFFIX')
+        self.assertTrue(ext_suffix.endswith(".pyd"))
+        self.assertTrue("mingw" in ext_suffix)
+        self.assertEqual(sysconfig.get_config_var('SHLIB_SUFFIX'), ".pyd")
+        ext_suffixes = importlib.machinery.EXTENSION_SUFFIXES
+        self.assertTrue(ext_suffix in ext_suffixes)
+        self.assertTrue(".pyd" in ext_suffixes)
+        if sysconfig.get_platform().startswith('mingw_i686'):
+             self.assertEqual(sys.winver, ".".join(map(str, sys.version_info[:2])) + '-32')
+        elif sysconfig.get_platform().startswith('mingw_aarch64'):
+            self.assertEqual(sys.winver, ".".join(map(str, sys.version_info[:2])) + '-arm64')
+        elif sysconfig.get_platform().startswith('mingw_armv7'):
+            self.assertEqual(sys.winver, ".".join(map(str, sys.version_info[:2])) + '-arm32')
+        else:
+            self.assertEqual(sys.winver, ".".join(map(str, sys.version_info[:2])))
+        self.assertEqual(platform.python_implementation(), "CPython")
+        self.assertEqual(platform.system(), "Windows")
+        self.assertTrue(isinstance(sys.api_version, int) and sys.api_version > 0)
+
+        with tempfile.TemporaryDirectory() as tmp:
+            builder = venv.EnvBuilder()
+            builder.create(tmp)
+            # This will not work in in-tree build
+            if not sysconfig.is_python_build():
+                op = subprocess.check_output(
+                    [
+                        os.path.join(tmp, "bin", "python.exe"),
+                        "-c",
+                        "import sysconfig; print(sysconfig.get_config_var('LIBDIR'))"
+                    ],
+                    cwd=tmp,
+                )
+                self.assertTrue(op.decode().strip().startswith(sys.base_prefix))
+
+    def test_sys_getpath(self):
+        # everything sourced from getpath.py
+        import sys
+
+        def assertNormpath(path):
+            self.assertEqual(path, os.path.normpath(path))
+
+        assertNormpath(sys.executable)
+        assertNormpath(sys._base_executable)
+        assertNormpath(sys.prefix)
+        assertNormpath(sys.base_prefix)
+        assertNormpath(sys.exec_prefix)
+        assertNormpath(sys.base_exec_prefix)
+        assertNormpath(sys.platlibdir)
+        assertNormpath(sys._stdlib_dir)
+        for p in sys.path:
+            assertNormpath(p)
+
+    def test_site(self):
+        import site
+
+        self.assertEqual(len(site.getsitepackages()), 1)
+
+    def test_c_ext_build(self):
+        import tempfile
+        import sys
+        import subprocess
+        import textwrap
+        import venv
+        from pathlib import Path
+
+        with tempfile.TemporaryDirectory() as tmppro:
+            builder = venv.EnvBuilder(with_pip=True)
+            builder.create(tmppro)
+            venv_exe = os.path.join(tmppro, "bin", os.path.basename(sys.executable))
+
+            with Path(tmppro, "setup.py").open("w") as f:
+                f.write(
+                    textwrap.dedent(
+                        """\
+                                    from setuptools import setup, Extension
+
+                                    setup(
+                                        name='cwrapper',
+                                        version='1.0',
+                                        ext_modules=[
+                                            Extension(
+                                                'cwrapper',
+                                                sources=['cwrapper.c']),
+                                        ],
+                                    )
+                                """
+                    )
+                )
+            with Path(tmppro, "cwrapper.c").open("w") as f:
+                f.write(
+                    textwrap.dedent(
+                        """\
+                                    #include <Python.h>
+                                    static PyObject *
+                                    helloworld(PyObject *self, PyObject *args)
+                                    {
+                                        printf("Hello World\\n");
+                                        Py_RETURN_NONE;
+                                    }
+                                    static PyMethodDef
+                                    myMethods[] = {
+                                        { "helloworld", helloworld, METH_NOARGS, "Prints Hello World" },
+                                        { NULL, NULL, 0, NULL }
+                                    };
+                                    static struct PyModuleDef cwrapper = {
+                                        PyModuleDef_HEAD_INIT,
+                                        "cwrapper",
+                                        "Test Module",
+                                        -1,
+                                        myMethods
+                                    };
+
+                                    PyMODINIT_FUNC
+                                    PyInit_cwrapper(void)
+                                    {
+                                        return PyModule_Create(&cwrapper);
+                                    }
+                                """
+                    )
+                )
+            subprocess.check_call(
+                [venv_exe, "-c", "import struct"],
+            )
+            subprocess.check_call(
+                [
+                    venv_exe,
+                    "-m",
+                    "pip",
+                    "install",
+                    tmppro,
+                ],
+            )
+            subprocess.check_call(
+                [venv_exe, "-c", "import cwrapper"],
+            )
+
+
+
+def suite():
+    return unittest.TestLoader().loadTestsFromName(__name__)
+
+
+if __name__ == '__main__':
+    unittest.main(defaultTest='suite')
diff --git a/pyconfig.h.in b/pyconfig.h.in
index df4d29fe5497a4..398b64f2f0be49 100644
--- a/pyconfig.h.in
+++ b/pyconfig.h.in
@@ -59,7 +59,7 @@
 /* Define to 1 if you have the `acosh' function. */
 #undef HAVE_ACOSH
 
-/* struct addrinfo (netdb.h) */
+/* struct addrinfo */
 #undef HAVE_ADDRINFO
 
 /* Define to 1 if you have the `alarm' function. */
@@ -1552,6 +1552,9 @@
 /* Define if mvwdelch in curses.h is an expression. */
 #undef MVWDELCH_IS_EXPRESSION
 
+/* Define to 1 if you want to use native NT threads */
+#undef NT_THREADS
+
 /* Define to the address where bug reports for this package should be sent. */
 #undef PACKAGE_BUGREPORT
 
@@ -1923,7 +1926,7 @@
 /* Define to `unsigned int' if <sys/types.h> does not define. */
 #undef size_t
 
-/* Define to `int' if <sys/socket.h> does not define. */
+/* Define to `int' if <sys/socket.h> or <ws2tcpip.h> does not define. */
 #undef socklen_t
 
 /* Define to `int' if <sys/types.h> doesn't define. */