[macOS] precompiled_headers target forces Clang-only flags which break build with GCC
For some reason CMake forces arch flags in Clang-only form if precompiled_headers target is enabled. This breaks the build with GCC:
g++-mp-13: error: unrecognized command-line option '-Xarch_ppc'
Real-life example: https://github.com/magiblot/turbo/issues/65#issuecomment-1905023218
The correct flag for GCC would be -arch ppc
(or -arch x86_64
etc.).
This is apparently a know issue: https://android.googlesource.com/platform/external/deqp-deps/glslang/+/refs/heads/main/CMakeLists.txt#99 However it is still unfixed, from the looks of things.