Ticket #30459: 30459.patch

../wp-includes/theme.php

@@ -128 +128 @@
  * @return bool true if a child theme is in use, false otherwise.
  **/
 function is_child_theme() {
-        return ( TEMPLATEPATH !== STYLESHEETPATH );
+        return ( get_template_directory() !== get_stylesheet_directory() );
 }
 
 /**