On master (https://github.com/bitcoin/bitcoin/commit/a6c3da131c855650e8888a9403776cfda0d0ee2e), building of libmultiprocess fails for the x86_64-w64-mingw32 target:
$ make -C depends libmultiprocess MULTIPROCESS=1 HOST=x86_64-w64-mingw32
...
Configuring libmultiprocess...
CMake Warning:
No source or binary directory provided. Both will be assumed to be the
same as the current working directory, but note that this warning will
become a fatal error in future CMake releases.
-- The CXX compiler identification is GNU 9.3.0
-- Check for working CXX compiler: /usr/bin/x86_64-w64-mingw32-g++-posix
-- Check for working CXX compiler: /usr/bin/x86_64-w64-mingw32-g++-posix -- broken
CMake Error at /usr/share/cmake-3.16/Modules/CMakeTestCXXCompiler.cmake:53 (message):
The C++ compiler
"/usr/bin/x86_64-w64-mingw32-g++-posix"
is not able to compile a simple test program.
It fails with the following output:
Change Dir: /home/hebasto/GitHub/bitcoin/depends/work/build/x86_64-w64-mingw32/libmultiprocess/d576d975debdc9090bd2582f83f49c76c0061698-7e18b85317d/CMakeFiles/CMakeTmp
Run Build Command(s):/usr/bin/make cmTC_14f5f/fast && make[1]: Entering directory '/home/hebasto/GitHub/bitcoin/depends/work/build/x86_64-w64-mingw32/libmultiprocess/d576d975debdc9090bd2582f83f49c76c0061698-7e18b85317d/CMakeFiles/CMakeTmp'
/usr/bin/make -f CMakeFiles/cmTC_14f5f.dir/build.make CMakeFiles/cmTC_14f5f.dir/build
make[2]: Entering directory '/home/hebasto/GitHub/bitcoin/depends/work/build/x86_64-w64-mingw32/libmultiprocess/d576d975debdc9090bd2582f83f49c76c0061698-7e18b85317d/CMakeFiles/CMakeTmp'
Building CXX object CMakeFiles/cmTC_14f5f.dir/testCXXCompiler.cxx.o
/usr/bin/x86_64-w64-mingw32-g++-posix -I/home/hebasto/GitHub/bitcoin/depends/x86_64-w64-mingw32/include -pipe -O2 -o CMakeFiles/cmTC_14f5f.dir/testCXXCompiler.cxx.o -c /home/hebasto/GitHub/bitcoin/depends/work/build/x86_64-w64-mingw32/libmultiprocess/d576d975debdc9090bd2582f83f49c76c0061698-7e18b85317d/CMakeFiles/CMakeTmp/testCXXCompiler.cxx
Linking CXX executable cmTC_14f5f
/usr/bin/cmake -E cmake_link_script CMakeFiles/cmTC_14f5f.dir/link.txt --verbose=1
/usr/bin/x86_64-w64-mingw32-g++-posix -I/home/hebasto/GitHub/bitcoin/depends/x86_64-w64-mingw32/include -pipe -O2 -L/home/hebasto/GitHub/bitcoin/depends/x86_64-w64-mingw32/lib -rdynamic CMakeFiles/cmTC_14f5f.dir/testCXXCompiler.cxx.o -o cmTC_14f5f
x86_64-w64-mingw32-g++-posix: error: unrecognized command line option ‘-rdynamic’
make[2]: *** [CMakeFiles/cmTC_14f5f.dir/build.make:87: cmTC_14f5f] Error 1
make[2]: Leaving directory '/home/hebasto/GitHub/bitcoin/depends/work/build/x86_64-w64-mingw32/libmultiprocess/d576d975debdc9090bd2582f83f49c76c0061698-7e18b85317d/CMakeFiles/CMakeTmp'
make[1]: *** [Makefile:121: cmTC_14f5f/fast] Error 2
make[1]: Leaving directory '/home/hebasto/GitHub/bitcoin/depends/work/build/x86_64-w64-mingw32/libmultiprocess/d576d975debdc9090bd2582f83f49c76c0061698-7e18b85317d/CMakeFiles/CMakeTmp'
CMake will not be able to correctly generate this project.
Call Stack (most recent call first):
CMakeLists.txt:6 (project)
-- Configuring incomplete, errors occurred!
