Merge dashpay#6079: backport: merge bitcoin#22433, bitcoin#22464, bitcoin#22845, bitcoin#23007, bitcoin#21920, bitcoin#21430, bitcoin#22133, bitcoin#23269, bitcoin#23494, bitcoin#20201, bitcoin#23947, bitcoin#22088, bitcoin#22093, partial bitcoin#20938 (build backports)

cc55ebb merge bitcoin#22093: Try posix-specific CXX first for mingw32 host (Kittywhiskers Van Gogh)
638806b merge bitcoin#22088: improve note on choosing posix mingw32 (Kittywhiskers Van Gogh)
7ad0141 merge bitcoin#23947: use host_os instead of TARGET_OS in configure output (Kittywhiskers Van Gogh)
9126006 merge bitcoin#20201: pkg-config related cleanup (Kittywhiskers Van Gogh)
77862d8 merge bitcoin#23494: minor boost tidyups (Kittywhiskers Van Gogh)
ef4b350 merge bitcoin#23269: remove redundant warning flags (Kittywhiskers Van Gogh)
183d08f merge bitcoin#22133: Make QWindowsVistaStylePlugin available again (Kittywhiskers Van Gogh)
1fbdd00 merge bitcoin#21430: Add -Werror=implicit-fallthrough compile flag (Kittywhiskers Van Gogh)
cae5496 merge bitcoin#21920: improve macro for testing -latomic requirement (Kittywhiskers Van Gogh)
78db324 partial bitcoin#20938: fix linking against -latomic when building for riscv (Kittywhiskers Van Gogh)
972b419 merge bitcoin#23007: remove WSL install instructions and point to upstream (Kittywhiskers Van Gogh)
54be58b merge bitcoin#22845: improve check for ::(w)system (Kittywhiskers Van Gogh)
5b86009 merge bitcoin#22464: fix 32-bit narrowing warning in bench/peer_eviction.cpp (Kittywhiskers Van Gogh)
a42202d merge bitcoin#22433: remove straggling boost thread_group related code (Kittywhiskers Van Gogh)
abdf4d7 build: use enough padding to match with labels in options printout (Kittywhiskers Van Gogh)
e22f421 doc: clean up `build-windows.md` (Kittywhiskers Van Gogh)

Pull request description:

  ## Breaking Changes

  None expected.

  ## Checklist:

  - [x] I have performed a self-review of my own code
  - [x] I have commented my code, particularly in hard-to-understand areas **(note: N/A)**
  - [x] I have added or updated relevant unit/integration/functional/e2e tests **(note: N/A)**
  - [x] I have made corresponding changes to the documentation
  - [x] I have assigned this pull request to a milestone _(for repository code-owners and collaborators only)_

ACKs for top commit:
  PastaPastaPasta:
    utACK [cc55ebb](dashpay@cc55ebb)

Tree-SHA512: f4cf6506120facabd5fc2e968c1b14a1fca02cf5858f63cce9e9743aa5327b18a7855b2584829eb568d6664a8e12c4bbfdda2f954ea44e29aaaba1776b3d1535

Author: PastaPastaPasta

build-aux/m4/bitcoin_find_bdb48.m4

@@ -91,7 +91,6 @@ AC_DEFUN([BITCOIN_FIND_BDB48],[
     fi
   fi
   if test "x$use_bdb" != "xno"; then
-    AC_SUBST(BDB_LIBS)
     AC_DEFINE([USE_BDB], [1], [Define if BDB support should be compiled in])
     use_bdb=yes
   fi

build-aux/m4/bitcoin_qt.m4

@@ -147,6 +147,7 @@ AC_DEFUN([BITCOIN_QT_CONFIGURE],[
       dnl https://bugreports.qt.io/browse/QTBUG-27097.
       AX_CHECK_LINK_FLAG([-lwtsapi32], [QT_LIBS="$QT_LIBS -lwtsapi32"], [AC_MSG_ERROR([could not link against -lwtsapi32])])
       _BITCOIN_QT_CHECK_STATIC_PLUGIN([QWindowsIntegrationPlugin], [-lqwindows])
+      _BITCOIN_QT_CHECK_STATIC_PLUGIN([QWindowsVistaStylePlugin], [-lqwindowsvistastyle])
       AC_DEFINE(QT_QPA_PLATFORM_WINDOWS, 1, [Define this symbol if the qt platform is windows])
     elif test "x$TARGET_OS" = xlinux; then
       _BITCOIN_QT_CHECK_STATIC_PLUGIN([QXcbIntegrationPlugin], [-lqxcb])
@@ -292,9 +293,7 @@ AC_DEFUN([BITCOIN_QT_CONFIGURE],[
   AC_SUBST(QT_LIBS)
   AC_SUBST(QT_LDFLAGS)
   AC_SUBST(QT_DBUS_INCLUDES)
-  AC_SUBST(QT_DBUS_LIBS)
   AC_SUBST(QT_TEST_INCLUDES)
-  AC_SUBST(QT_TEST_LIBS)
   AC_SUBST(QT_SELECT, qt5)
   AC_SUBST(MOC_DEFS)
 ])

build-aux/m4/l_atomic.m4

@@ -12,8 +12,17 @@ dnl warranty.
 m4_define([_CHECK_ATOMIC_testbody], [[
   #include <atomic>
   #include <cstdint>
+  #include <chrono>
+
+  using namespace std::chrono_literals;
 
   int main() {
+    std::atomic<bool> lock{true};
+    std::atomic_exchange(&lock, false);
+
+    std::atomic<std::chrono::seconds> t{0s};
+    t.store(2s);
+
     std::atomic<int64_t> a{};
 
     int64_t v = 5;

configure.ac

@@ -468,6 +468,7 @@ if test "x$enable_werror" = "xyes"; then
                         [AC_LANG_SOURCE([[struct A { virtual void f(); }; struct B : A { void f() final; };]])])
   AX_CHECK_COMPILE_FLAG([-Werror=unreachable-code-loop-increment],[ERROR_CXXFLAGS="$ERROR_CXXFLAGS -Werror=unreachable-code-loop-increment"],,[[$CXXFLAG_WERROR]])
   AX_CHECK_COMPILE_FLAG([-Werror=mismatched-tags], [ERROR_CXXFLAGS="$ERROR_CXXFLAGS -Werror=mismatched-tags"], [], [$CXXFLAG_WERROR])
+  AX_CHECK_COMPILE_FLAG([-Werror=implicit-fallthrough], [ERROR_CXXFLAGS="$ERROR_CXXFLAGS -Werror=implicit-fallthrough"], [], [$CXXFLAG_WERROR])
 fi
 
 if test "x$CXXFLAGS_overridden" = "xno"; then
@@ -478,30 +479,26 @@ if test "x$CXXFLAGS_overridden" = "xno"; then
   AX_CHECK_COMPILE_FLAG([-Wformat -Wformat-security],[WARN_CXXFLAGS="$WARN_CXXFLAGS -Wformat -Wformat-security"],,[[$CXXFLAG_WERROR]])
   AX_CHECK_COMPILE_FLAG([-Wvla],[WARN_CXXFLAGS="$WARN_CXXFLAGS -Wvla"],,[[$CXXFLAG_WERROR]])
   AX_CHECK_COMPILE_FLAG([-Wshadow-field],[WARN_CXXFLAGS="$WARN_CXXFLAGS -Wshadow-field"],,[[$CXXFLAG_WERROR]])
-  AX_CHECK_COMPILE_FLAG([-Wswitch],[WARN_CXXFLAGS="$WARN_CXXFLAGS -Wswitch"],,[[$CXXFLAG_WERROR]])
   AX_CHECK_COMPILE_FLAG([-Wthread-safety],[WARN_CXXFLAGS="$WARN_CXXFLAGS -Wthread-safety"],,[[$CXXFLAG_WERROR]])
-  AX_CHECK_COMPILE_FLAG([-Wrange-loop-analysis],[WARN_CXXFLAGS="$WARN_CXXFLAGS -Wrange-loop-analysis"],,[[$CXXFLAG_WERROR]])
+  AX_CHECK_COMPILE_FLAG([-Wloop-analysis],[WARN_CXXFLAGS="$WARN_CXXFLAGS -Wloop-analysis"],,[[$CXXFLAG_WERROR]])
   AX_CHECK_COMPILE_FLAG([-Wredundant-decls],[WARN_CXXFLAGS="$WARN_CXXFLAGS -Wredundant-decls"],,[[$CXXFLAG_WERROR]])
-  AX_CHECK_COMPILE_FLAG([-Wunused-variable],[WARN_CXXFLAGS="$WARN_CXXFLAGS -Wunused-variable"],,[[$CXXFLAG_WERROR]])
   AX_CHECK_COMPILE_FLAG([-Wunused-member-function],[WARN_CXXFLAGS="$WARN_CXXFLAGS -Wunused-member-function"],,[[$CXXFLAG_WERROR]])
   AX_CHECK_COMPILE_FLAG([-Wdate-time],[WARN_CXXFLAGS="$WARN_CXXFLAGS -Wdate-time"],,[[$CXXFLAG_WERROR]])
   AX_CHECK_COMPILE_FLAG([-Wconditional-uninitialized],[WARN_CXXFLAGS="$WARN_CXXFLAGS -Wconditional-uninitialized"],,[[$CXXFLAG_WERROR]])
-  AX_CHECK_COMPILE_FLAG([-Wsign-compare],[WARN_CXXFLAGS="$WARN_CXXFLAGS -Wsign-compare"],,[[$CXXFLAG_WERROR]])
   AX_CHECK_COMPILE_FLAG([-Wduplicated-branches],[WARN_CXXFLAGS="$WARN_CXXFLAGS -Wduplicated-branches"],,[[$CXXFLAG_WERROR]])
   AX_CHECK_COMPILE_FLAG([-Wduplicated-cond],[WARN_CXXFLAGS="$WARN_CXXFLAGS -Wduplicated-cond"],,[[$CXXFLAG_WERROR]])
   AX_CHECK_COMPILE_FLAG([-Wlogical-op],[WARN_CXXFLAGS="$WARN_CXXFLAGS -Wlogical-op"],,[[$CXXFLAG_WERROR]])
   AX_CHECK_COMPILE_FLAG([-Woverloaded-virtual],[WARN_CXXFLAGS="$WARN_CXXFLAGS -Woverloaded-virtual"],,[[$CXXFLAG_WERROR]])
   AX_CHECK_COMPILE_FLAG([-Wsuggest-override],[WARN_CXXFLAGS="$WARN_CXXFLAGS -Wsuggest-override"],,[[$CXXFLAG_WERROR]],
                         [AC_LANG_SOURCE([[struct A { virtual void f(); }; struct B : A { void f() final; };]])])
   AX_CHECK_COMPILE_FLAG([-Wunreachable-code-loop-increment],[WARN_CXXFLAGS="$WARN_CXXFLAGS -Wunreachable-code-loop-increment"],,[[$CXXFLAG_WERROR]])
+  AX_CHECK_COMPILE_FLAG([-Wimplicit-fallthrough], [WARN_CXXFLAGS="$WARN_CXXFLAGS -Wimplicit-fallthrough"], [], [$CXXFLAG_WERROR])
 
   dnl Some compilers (gcc) ignore unknown -Wno-* options, but warn about all
   dnl unknown options if any other warning is produced. Test the -Wfoo case, and
   dnl set the -Wno-foo case if it works.
   AX_CHECK_COMPILE_FLAG([-Wunused-parameter],[NOWARN_CXXFLAGS="$NOWARN_CXXFLAGS -Wno-unused-parameter"],,[[$CXXFLAG_WERROR]])
   AX_CHECK_COMPILE_FLAG([-Wself-assign],[NOWARN_CXXFLAGS="$NOWARN_CXXFLAGS -Wno-self-assign"],,[[$CXXFLAG_WERROR]])
-  AX_CHECK_COMPILE_FLAG([-Wunused-local-typedef],[NOWARN_CXXFLAGS="$NOWARN_CXXFLAGS -Wno-unused-local-typedef"],,[[$CXXFLAG_WERROR]])
-  AX_CHECK_COMPILE_FLAG([-Wimplicit-fallthrough],[NOWARN_CXXFLAGS="$NOWARN_CXXFLAGS -Wno-implicit-fallthrough"],,[[$CXXFLAG_WERROR]])
   if test x$suppress_external_warnings != xyes ; then
     AX_CHECK_COMPILE_FLAG([-Wdeprecated-copy],[NOWARN_CXXFLAGS="$NOWARN_CXXFLAGS -Wno-deprecated-copy"],,[[$CXXFLAG_WERROR]])
   fi
@@ -1272,13 +1269,14 @@ AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
  [ AC_MSG_RESULT(no); HAVE_STRONG_GETAUXVAL=0 ]
 )
 
+have_any_system=no
 AC_MSG_CHECKING([for std::system])
 AC_LINK_IFELSE(
     [ AC_LANG_PROGRAM(
         [[ #include <cstdlib> ]],
         [[ int nErr = std::system(""); ]]
     )],
-    [ AC_MSG_RESULT(yes); AC_DEFINE(HAVE_STD__SYSTEM, 1, Define to 1 if you have the `std::system' function.)],
+    [ AC_MSG_RESULT(yes); have_any_system=yes],
     [ AC_MSG_RESULT(no) ]
 )
 
@@ -1288,12 +1286,13 @@ AC_LINK_IFELSE(
         [[ #include <stdlib.h> ]],
         [[ int nErr = ::_wsystem(NULL); ]]
     )],
-    [ AC_MSG_RESULT(yes); AC_DEFINE(HAVE_WSYSTEM, 1, Define to 1 if you have the `::wsystem' function.)],
+    [ AC_MSG_RESULT(yes); have_any_system=yes],
     [ AC_MSG_RESULT(no) ]
 )
 
-# Define to 1 if std::system or ::wsystem (Windows) is available
-AC_DEFINE([HAVE_SYSTEM], [HAVE_STD__SYSTEM || HAVE_WSYSTEM], [std::system or ::wsystem])
+if test "x$have_any_system" != "xno"; then
+  AC_DEFINE(HAVE_SYSTEM, 1, Define to 1 if std::system or ::wsystem is available.)
+fi
 
 dnl SUPPRESSED_CPPFLAGS=SUPPRESS_WARNINGS([$SOME_CPPFLAGS])
 dnl Replace -I with -isystem in $SOME_CPPFLAGS to suppress warnings from
@@ -1585,15 +1584,13 @@ dnl libmultiprocess library check
 
 libmultiprocess_found=no
 if test "x$with_libmultiprocess" = xyes || test "x$with_libmultiprocess" = xauto; then
-  m4_ifdef([PKG_CHECK_MODULES], [PKG_CHECK_MODULES([LIBMULTIPROCESS], [libmultiprocess], [
+  PKG_CHECK_MODULES([LIBMULTIPROCESS], [libmultiprocess], [
      libmultiprocess_found=yes;
      libmultiprocess_prefix=`$PKG_CONFIG --variable=prefix libmultiprocess`;
-  ], [true])])
+  ], [true])
 elif test "x$with_libmultiprocess" != xno; then
   AC_MSG_ERROR([--with-libmultiprocess=$with_libmultiprocess value is not yes, auto, or no])
 fi
-AC_SUBST(LIBMULTIPROCESS_CFLAGS)
-AC_SUBST(LIBMULTIPROCESS_LIBS)
 
 dnl Enable multiprocess check
 
@@ -1882,17 +1879,12 @@ AC_SUBST(USE_BDB)
 AC_SUBST(USE_UPNP)
 AC_SUBST(USE_QRCODE)
 AC_SUBST(BOOST_LIBS)
-AC_SUBST(SQLITE_LIBS)
 AC_SUBST(TESTDEFS)
 AC_SUBST(MINIUPNPC_CPPFLAGS)
 AC_SUBST(MINIUPNPC_LIBS)
 AC_SUBST(GMP_LIBS)
 AC_SUBST(NATPMP_CPPFLAGS)
 AC_SUBST(NATPMP_LIBS)
-AC_SUBST(EVENT_LIBS)
-AC_SUBST(EVENT_PTHREADS_LIBS)
-AC_SUBST(ZMQ_LIBS)
-AC_SUBST(QR_LIBS)
 AC_SUBST(DSYMUTIL_FLAT)
 AC_SUBST(HAVE_FDATASYNC)
 AC_SUBST(HAVE_FULLFSYNC)
@@ -1947,9 +1939,9 @@ esac
 
 echo
 echo "Options used to compile and link:"
-echo "  boost process = $with_boost_process"
-echo "  multiprocess  = $build_multiprocess"
-echo "  with libs     = $build_bitcoin_libs"
+echo "  boost process       = $with_boost_process"
+echo "  multiprocess        = $build_multiprocess"
+echo "  with libs           = $build_bitcoin_libs"
 echo "  with wallet         = $enable_wallet"
 echo "  with gui / qt       = $bitcoin_enable_qt"
 if test "x$enable_wallet" != "xno"; then
@@ -1979,7 +1971,7 @@ echo "  miner enabled       = $enable_miner"
 echo "  gprof enabled       = $enable_gprof"
 echo "  werror              = $enable_werror"
 echo
-echo "  target os           = $TARGET_OS"
+echo "  target os           = $host_os"
 echo "  build os            = $build_os"
 echo
 echo "  CC                  = $CC"

depends/hosts/mingw32.mk

@@ -1,3 +1,7 @@
+ifneq ($(shell which $(host)-g++-posix),)
+mingw32_CXX := $(host)-g++-posix
+endif
+
 mingw32_CFLAGS=-pipe
 mingw32_CXXFLAGS=$(mingw32_CFLAGS)
 

depends/packages/boost.mk

@@ -31,7 +31,7 @@ else
 $(package)_toolset_$(host_os)=gcc
 endif
 $(package)_config_libraries=filesystem,test
-$(package)_cxxflags=-std=c++17 -fvisibility=hidden
+$(package)_cxxflags=-std=c++17
 $(package)_cxxflags_linux=-fPIC
 $(package)_cxxflags_freebsd=-fPIC
 $(package)_cxxflags_openbsd=-fPIC
@@ -54,5 +54,5 @@ define $(package)_build_cmds
 endef
 
 define $(package)_stage_cmds
-  b2 -d0 -j4 --prefix=$($(package)_staging_prefix_dir) $($(package)_config_opts) toolset=$($(package)_toolset_$(host_os)) install
+  b2 -d0 -j4 --prefix=$($(package)_staging_prefix_dir) $($(package)_config_opts) toolset=$($(package)_toolset_$(host_os)) --no-cmake-config install
 endef

doc/build-windows.md

@@ -5,11 +5,8 @@ Below are some notes on how to build Dash Core for Windows.
 
 The options known to work for building Dash Core on Windows are:
 
-* On Linux, using the [Mingw-w64](https://mingw-w64.org/doku.php) cross compiler tool chain. Ubuntu Focal 20.04 is required
-and is the platform used to build the Dash Core Windows release binaries.
-* On Windows, using [Windows
-Subsystem for Linux (WSL)](https://docs.microsoft.com/windows/wsl/about) and the Mingw-w64 cross compiler tool chain.
-* On Windows, using a native compiler tool chain such as [Visual Studio](https://www.visualstudio.com).
+* On Linux, using the [Mingw-w64](https://www.mingw-w64.org/) cross compiler tool chain.
+* On Windows, using [Windows Subsystem for Linux (WSL)](https://docs.microsoft.com/windows/wsl/about) and Mingw-w64.
 
 Other options which may work, but which have not been extensively tested are (please contribute instructions):
 
@@ -18,86 +15,51 @@ Other options which may work, but which have not been extensively tested are (pl
 Installing Windows Subsystem for Linux
 ---------------------------------------
 
-With Windows 10, Microsoft has released a new feature named the [Windows
-Subsystem for Linux (WSL)](https://docs.microsoft.com/windows/wsl/about). This
-feature allows you to run a bash shell directly on Windows in an Ubuntu-based
-environment. Within this environment you can cross compile for Windows without
-the need for a separate Linux VM or server. Note that while WSL can be installed with
-other Linux variants, such as OpenSUSE, the following instructions have only been
-tested with Ubuntu.
-
-This feature is not supported in versions of Windows prior to Windows 10 or on
-Windows Server SKUs. In addition, it is available [only for 64-bit versions of
-Windows](https://docs.microsoft.com/windows/wsl/install-win10).
-
-Full instructions to install WSL are available on the above link.
-To install WSL on Windows 10 with Fall Creators Update installed (version >= 16215.0) do the following:
-
-1. Enable the Windows Subsystem for Linux feature
-  * Open the Windows Features dialog (`OptionalFeatures.exe`)
-  * Enable 'Windows Subsystem for Linux'
-  * Click 'OK' and restart if necessary
-2. Install Ubuntu
-  * Open Microsoft Store and search for "Ubuntu 20.04" or use [this link](https://www.microsoft.com/store/productId/9MTTCL66CPXJ)
-  * Click Install
-3. Complete Installation
-  * Open a cmd prompt and type "Ubuntu2004"
-  * Create a new UNIX user account (this is a separate account from your Windows account)
-
-After the bash shell is active, you can follow the instructions below, starting
-with the "Cross-compilation" section. Compiling the 64-bit version is
-recommended, but it is possible to compile the 32-bit version.
+Follow the upstream installation instructions, available [here](https://docs.microsoft.com/windows/wsl/install-win10).
 
 Cross-compilation
 -------------------
 
-These steps can be performed on, for example, an Ubuntu VM. The depends system
+The steps below can be performed on Ubuntu or WSL. The depends system
 will also work on other Linux distributions, however the commands for
 installing the toolchain will be different.
 
 First, install the general dependencies:
 
-    sudo apt-get install build-essential libtool autotools-dev automake pkg-config bsdmainutils bison curl
+    sudo apt-get install build-essential libtool autotools-dev automake pkg-config bsdmainutils curl git bison
 
 A host toolchain (`build-essential`) is necessary because some dependency
-packages (such as `protobuf`) need to build host utilities that are used in the
-build process.
+packages need to build host utilities that are used in the build process.
+
+See [dependencies.md](dependencies.md) for a complete overview.
 
 ## Building for 64-bit Windows
 
-To build executables for Windows 64-bit, install the following dependencies:
+The first step is to install the mingw-w64 cross-compilation tool chain:
 
     sudo apt-get install g++-mingw-w64-x86-64 mingw-w64-x86-64-dev
 
-Then build using:
-
-    cd depends
-    make HOST=x86_64-w64-mingw32
-    cd ..
-    ./autogen.sh # not required when building from tarball
-    CONFIG_SITE=$PWD/depends/x86_64-w64-mingw32/share/config.site ./configure --prefix=/
-    make
-
-## Building for 32-bit Windows
-
-To build executables for Windows 32-bit, install the following dependencies:
+Once the toolchain is installed the build steps are common:
 
-    sudo apt-get install g++-mingw-w64-i686 mingw-w64-i686-dev
+Note that for WSL the Dash Core source path MUST be somewhere in the default mount file system, for
+example /usr/src/dash, AND not under /mnt/d/. If this is not the case the dependency autoconf scripts will fail.
+This means you cannot use a directory that is located directly on the host Windows file system to perform the build.
 
 Additional WSL Note: WSL support for [launching Win32 applications](https://docs.microsoft.com/en-us/archive/blogs/wsl/windows-and-ubuntu-interoperability#launching-win32-applications-from-within-wsl)
 results in `Autoconf` configure scripts being able to execute Windows Portable Executable files. This can cause
 unexpected behaviour during the build, such as Win32 error dialogs for missing libraries. The recommended approach
 is to temporarily disable WSL support for Win32 applications.
 
-Then build using:
+Build using:
 
+    PATH=$(echo "$PATH" | sed -e 's/:\/mnt.*//g') # strip out problematic Windows %PATH% imported var
     sudo bash -c "echo 0 > /proc/sys/fs/binfmt_misc/status" # Disable WSL support for Win32 applications.
     cd depends
-    make HOST=i686-w64-mingw32
+    make HOST=x86_64-w64-mingw32
     cd ..
     ./autogen.sh
-    CONFIG_SITE=$PWD/depends/i686-w64-mingw32/share/config.site ./configure --prefix=/
-    make
+    CONFIG_SITE=$PWD/depends/x86_64-w64-mingw32/share/config.site ./configure --prefix=/
+    make # use "-j N" for N parallel jobs
     sudo bash -c "echo 1 > /proc/sys/fs/binfmt_misc/status" # Enable WSL support for Win32 applications.
 
 ## Depends system

src/Makefile.leveldb.include

@@ -22,6 +22,7 @@ LEVELDB_CPPFLAGS_INT += -DHAVE_SNAPPY=0 -DHAVE_CRC32C=1
 LEVELDB_CPPFLAGS_INT += -DHAVE_FDATASYNC=@HAVE_FDATASYNC@
 LEVELDB_CPPFLAGS_INT += -DHAVE_FULLFSYNC=@HAVE_FULLFSYNC@
 LEVELDB_CPPFLAGS_INT += -DHAVE_O_CLOEXEC=@HAVE_O_CLOEXEC@
+LEVELDB_CPPFLAGS_INT += -DFALLTHROUGH_INTENDED=[[fallthrough]]
 
 if WORDS_BIGENDIAN
 LEVELDB_CPPFLAGS_INT += -DLEVELDB_IS_BIG_ENDIAN=1

src/bench/peer_eviction.cpp

@@ -27,7 +27,8 @@ static void EvictionProtectionCommon(
         candidate_setup_fn(c);
     }
 
-    std::vector<Candidates> copies{bench.epochs() * bench.epochIterations(), candidates};
+    std::vector<Candidates> copies{
+        static_cast<size_t>(bench.epochs() * bench.epochIterations()), candidates};
     size_t i{0};
     bench.run([&] {
         ProtectEvictionCandidatesByRatio(copies.at(i));

src/hash.cpp

@@ -47,8 +47,10 @@ unsigned int MurmurHash3(unsigned int nHashSeed, Span<const unsigned char> vData
     switch (vDataToHash.size() & 3) {
         case 3:
             k1 ^= tail[2] << 16;
+            [[fallthrough]];
         case 2:
             k1 ^= tail[1] << 8;
+            [[fallthrough]];
         case 1:
             k1 ^= tail[0];
             k1 *= c1;