cmake HAS_X86_64_FLAG_ examples

beyond-all-reason/RecoilEngine rts/build/cmake/TestCXXFlags.cmake :89 

check_cxx_accepts_flag("-march=x86_64" HAS_X86_64_FLAG_)

beyond-all-reason/RecoilEngine rts/build/cmake/TestCXXFlags.cmake :92 

endif (HAS_X86_64_FLAG_)