cmake HAVE_CONSTRUCTOR_ATTRIBUTE examples

FujiNetWIFI/fujinet-firmware components_pc/libssh/ConfigureChecks.cmake :336

check_c_source_compiles("
void test_constructor_attribute(void) __attribute__ ((constructor));

void test_constructor_attribute(void)
{
    return;
}

int main(void) {
    return 0;
}" HAVE_CONSTRUCTOR_ATTRIBUTE)