What's up with all the hardcoded paths in
CMakeLists.txt? You need none of that. Remove both Sets and include_directories (also drop .exe from the project name). Make sure you have installed pacman -S mingw-w64-ucrt-x86_64-gcc mingw-w64-ucrt-x86_64-cmake as opposed to just gcc and cmake. And you definitely don't want anything in C:\msys64\usr to participate in the build, that's for a different environment. If this doesn't work, please show the new CMake logs.