cmake AWS_HAVE_WINAPI_DESKTOP examples

pingcap/tiflash contrib/aws-cmake/AwsFeatureTests.cmake :46

check_c_source_compiles("
    #include <Windows.h>
    #if WINAPI_FAMILY_PARTITION(WINAPI_PARTITION_DESKTOP)
    int main() {
        return 0;
    }
    #else
    it's not windows desktop
    #endif
" AWS_HAVE_WINAPI_DESKTOP)