Fix xml opt with XML_ENABLE macro

core/register_core_types.cpp

@@ -101,10 +101,12 @@ void register_core_types() {
 	resource_loader_binary = memnew( ResourceFormatLoaderBinary );
 	ResourceLoader::add_resource_format_loader(resource_loader_binary);
 
+#ifdef XML_ENABLED
 	resource_saver_xml = memnew( ResourceFormatSaverXML );
 	ResourceSaver::add_resource_format_saver(resource_saver_xml);
 	resource_loader_xml = memnew( ResourceFormatLoaderXML );
 	ResourceLoader::add_resource_format_loader(resource_loader_xml);
+#endif
 
 	ObjectTypeDB::register_type<Object>();