NSObject and NSRunLoop updates for MacOS-X compatibility

git-svn-id: svn+ssh://svn.gna.org/svn/gnustep/libs/base/trunk@14349 72102866-910b-0410-8b05-ffd578937521

Source/NSObject.m

@@ -1494,6 +1494,14 @@ static BOOL double_release_check_enabled = NO;
   return NO;
 }
 
+/**
+ * Returns YES if the receiver is aClass or a subclass of aClass.
+ */
++ (BOOL) isSubclassOfClass: (Class)aClass
+{
+  return GSObjCIsKindOf(self, aClass);
+}
+
 /**
  * Causes the receiver to execute the method implementation corresponding
  * to aSelector and returns the result.<br />