charconv cannot be built with MinGW 13.2.0 due to missing extern "C"

[TsXor]

boost: 1.85.0 release 7z ball

build commands:

./bootstrap.bat mingw
./b2 toolset=gcc

gcc version: (installed with choco install mingw)

PS > gcc -v
Using built-in specs.
COLLECT_GCC=C:\ProgramData\mingw64\mingw64\bin\gcc.exe
COLLECT_LTO_WRAPPER=C:/ProgramData/mingw64/mingw64/bin/../libexec/gcc/x86_64-w64-mingw32/13.2.0/lto-wrapper.exe
Target: x86_64-w64-mingw32
Configured with: ../../../src/gcc-13.2.0/configure --host=x86_64-w64-mingw32 --build=x86_64-w64-mingw32 --target=x86_64-w64-mingw32 --prefix=/mingw64 --with-sysroot=/c/buildroot/x86_64-1320-posix-seh-ucrt-rt_v11-rev0/mingw64 --enable-host-shared --disable-multilib --enable-languages=c,c++,fortran,lto --enable-libstdcxx-time=yes --enable-threads=posix --enable-libgomp --enable-libatomic --enable-lto --enable-graphite --enable-checking=release --enable-fully-dynamic-string --enable-version-specific-runtime-libs --enable-libstdcxx-filesystem-ts=yes --disable-libssp --disable-libstdcxx-pch --disable-libstdcxx-debug --enable-bootstrap --disable-rpath --disable-win32-registry --disable-nls --disable-werror --disable-symvers --with-gnu-as --with-gnu-ld --with-arch=nocona --with-tune=core2 --with-libiconv --with-system-zlib --with-gmp=/c/buildroot/prerequisites/x86_64-w64-mingw32-static --with-mpfr=/c/buildroot/prerequisites/x86_64-w64-mingw32-static --with-mpc=/c/buildroot/prerequisites/x86_64-w64-mingw32-static --with-isl=/c/buildroot/prerequisites/x86_64-w64-mingw32-static --with-pkgversion='x86_64-posix-seh-rev0, Built by MinGW-Builds project' --with-bugurl=https://github.com/niXman/mingw-builds CFLAGS='-O2 -pipe -fno-ident -I/c/buildroot/x86_64-1320-posix-seh-ucrt-rt_v11-rev0/mingw64/opt/include -I/c/buildroot/prerequisites/x86_64-zlib-static/include -I/c/buildroot/prerequisites/x86_64-w64-mingw32-static/include' CXXFLAGS='-O2 -pipe -fno-ident -I/c/buildroot/x86_64-1320-posix-seh-ucrt-rt_v11-rev0/mingw64/opt/include -I/c/buildroot/prerequisites/x86_64-zlib-static/include -I/c/buildroot/prerequisites/x86_64-w64-mingw32-static/include' CPPFLAGS=' -I/c/buildroot/x86_64-1320-posix-seh-ucrt-rt_v11-rev0/mingw64/opt/include -I/c/buildroot/prerequisites/x86_64-zlib-static/include -I/c/buildroot/prerequisites/x86_64-w64-mingw32-static/include' LDFLAGS='-pipe -fno-ident -L/c/buildroot/x86_64-1320-posix-seh-ucrt-rt_v11-rev0/mingw64/opt/lib -L/c/buildroot/prerequisites/x86_64-zlib-static/lib -L/c/buildroot/prerequisites/x86_64-w64-mingw32-static/lib ' LD_FOR_TARGET=/c/buildroot/x86_64-1320-posix-seh-ucrt-rt_v11-rev0/mingw64/bin/ld.exe --with-boot-ldflags=' -Wl,--disable-dynamicbase -static-libstdc++ -static-libgcc'
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 13.2.0 (x86_64-posix-seh-rev0, Built by MinGW-Builds project)

build output: build_fail.log

By reading the error info, I found that it is caused by language linkage, and there should be somewhere missing extern "C" wrapping.
It turned out that x86intrin.h have no extern "C" wrapping, but ./boost/charconv/detail/config.hpp:82 doesn't know this.

charconv/include/boost/charconv/detail/config.hpp

Line 82 in ecdca08

# include <x86intrin.h>

After wrapping it like the following, I could successfully compile charconv.

extern "C" {
#  include <x86intrin.h>
}

build output with patch above: build_patched.log