Prevent stack overflow in GNUstep menu code

* src/nsmenu.m (ns_update_menubar): Always do a deep update for
GNUstep.
([EmacsMenu menuNeedsUpdate:]): Don't update the menu as it should
always have had a deep update.

src/nsmenu.m

@@ -145,6 +145,10 @@
   t = -(1000*tb.time+tb.millitm);
 #endif
 
+#ifdef NS_IMPL_GNUSTEP
+  deep_p = 1; /* See comment in menuNeedsUpdate.  */
+#endif
+
   if (deep_p)
     {
       /* Make a widget-value tree representing the entire menu trees.  */
@@ -433,21 +437,22 @@ - (instancetype)initWithTitle: (NSString *)title
 }
 
 
-/* Delegate method called when a submenu is being opened: run a 'deep' call
-   to set_frame_menubar.  */
-
-/* TODO: GNUstep calls this method when the menu is still being built
-   which throws it into an infinite loop.  One possible solution is to
-   use menuWillOpen instead, but the Apple docs explicitly warn
-   against changing the contents of the menu in it.  I don't know what
-   the right thing to do for GNUstep is.  */
+/* Delegate method called when a submenu is being opened: run a 'deep'
+   call to ns_update_menubar.  */
 - (void)menuNeedsUpdate: (NSMenu *)menu
 {
   if (!FRAME_LIVE_P (SELECTED_FRAME ()))
     return;
 
+#ifdef NS_IMPL_COCOA
+/* TODO: GNUstep calls this method when the menu is still being built
+   which results in a recursive stack overflow.  One possible solution
+   is to use menuWillOpen instead, but the Apple docs explicitly warn
+   against changing the contents of the menu in it.  I don't know what
+   the right thing to do for GNUstep is.  */
   if (needsUpdate)
     ns_update_menubar (SELECTED_FRAME (), true);
+#endif
 }