include(CheckCCompilerFlag) function(test_and_set_c_compiler_flag_global _flag) string(REGEX REPLACE "-" "_" _sflag ${_flag}) set(CMAKE_REQUIRED_FLAGS ${_flag}) check_c_compiler_flag(${_flag} COMPILER_SUPPORTS_FLAG_${_sflag}) if(COMPILER_SUPPORTS_FLAG_${_sflag}) set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${_flag}" PARENT_SCOPE) endif() endfunction(test_and_set_c_compiler_flag_global)