check_c_source_compiles("
#define FALL_THROUGH __attribute__((fallthrough))

int main(void) {
    int i = 2;

    switch (i) {
    case 0:
        FALL_THROUGH;
    case 1:
        break;
    default:
        break;
    }

    return 0;
}" HAVE_FALLTHROUGH_ATTRIBUTE)