@@ -29,10 +29,11 @@
 @interface OFRecursiveMutex: OFObject <OFLocking>
 {
 	OFPlainRecursiveMutex _rmutex;
 	bool _initialized;
 	OFString *_Nullable _name;
+	OF_RESERVE_IVARS(OFRecursiveMutex, 4)
 }
 
 /**
  * @brief Creates a new recursive mutex.
  *