Fix #if *_ENABLED inconsistencies, should check if defined

Co-authored-by: Caroline Joy Bell <halotroop2288@proton.me>

modules/mono/utils/path_utils.cpp

@@ -152,7 +152,7 @@ String realpath(const String &p_path) {
 	}
 
 	return result.simplify_path();
-#elif UNIX_ENABLED
+#elif defined(UNIX_ENABLED)
 	char *resolved_path = ::realpath(p_path.utf8().get_data(), nullptr);
 
 	if (!resolved_path) {