include(CheckCXXCompilerFlag)

macro (append_compile_flag _flag)
    string (MAKE_C_IDENTIFIER ${_flag} _name)

    if (NOT DEFINED compile_flag_${_name})
        check_cxx_compiler_flag (${_flag} compile_flag_${_name})
    endif ()

    if (compile_flag_${_name})
        set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${_flag}")
    endif()
endmacro(append_compile_flag)