Revert "Simplify sys.abiflags in sysconfig and site"

This reverts commit 7884a62.

Author: XuehaiPan

Lib/site.py

@@ -75,6 +75,7 @@
 import _sitebuiltins
 import io
 import stat
+import warnings
 
 # Prefixes for site-packages; add additional prefixes like /usr/local here
 PREFIXES = [sys.prefix, sys.exec_prefix]
@@ -318,6 +319,15 @@ def joinuser(*args):
 # Same to sysconfig.get_path('purelib', os.name+'_user')
 def _get_path(userbase):
     version = sys.version_info
+    with warnings.catch_warnings():
+        # ignore DeprecationWarning on sys.abiflags change on Windows
+        warnings.simplefilter('ignore', DeprecationWarning)
+        abiflags = getattr(sys, 'abiflags', '')
+    if 't' in abiflags:
+        abi_thread = 't'
+    else:
+        abi_thread = ''
+
     implementation = _get_implementation()
     implementation_lower = implementation.lower()
     if os.name == 'nt':
@@ -327,7 +337,6 @@ def _get_path(userbase):
     if sys.platform == 'darwin' and sys._framework:
         return f'{userbase}/lib/{implementation_lower}/site-packages'
 
-    abi_thread = 't' if 't' in sys.abiflags else ''
     return f'{userbase}/lib/python{version[0]}.{version[1]}{abi_thread}/site-packages'
 
 
@@ -396,8 +405,15 @@ def getsitepackages(prefixes=None):
 
         implementation = _get_implementation().lower()
         ver = sys.version_info
-        if os.name != 'nt':
-            abi_thread = 't' if 't' in sys.abiflags else ''
+        with warnings.catch_warnings():
+            # ignore DeprecationWarning on sys.abiflags change on Windows
+            warnings.simplefilter('ignore', DeprecationWarning)
+            abiflags = getattr(sys, 'abiflags', '')
+        if 't' in abiflags:
+            abi_thread = 't'
+        else:
+            abi_thread = ''
+        if os.sep == '/':
             libdirs = [sys.platlibdir]
             if sys.platlibdir != "lib":
                 libdirs.append("lib")

Lib/sysconfig/__init__.py

@@ -325,6 +325,7 @@ def get_default_scheme():
 
 def get_makefile_filename():
     """Return the path of the Makefile."""
+    import warnings
 
     # GH-127429: When cross-compiling, use the Makefile from the target, instead of the host Python.
     if cross_base := os.environ.get('_PYTHON_PROJECT_BASE'):
@@ -333,7 +334,12 @@ def get_makefile_filename():
     if _PYTHON_BUILD:
         return os.path.join(_PROJECT_BASE, "Makefile")
 
-    if os.name == 'nt':
+    with warnings.catch_warnings():
+        # ignore DeprecationWarning on sys.abiflags change on Windows
+        warnings.simplefilter('ignore', DeprecationWarning)
+        has_abiflags = hasattr(sys, 'abiflags')
+
+    if has_abiflags:
         config_dir_name = f'config-{_PY_VERSION_SHORT}{sys.abiflags}'
     else:
         config_dir_name = 'config'