Fix GNUstep warnings

* src/nsterm.h: EmacsSurface is only required if NS_DRAW_TO_BUFFER is
defined.
* src/nsterm.m (ns_judge_scroll_bars): Remove unused variable.
* src/nsmenu.m (update_frame_tool_bar):
(ns_update_menubar): Remove unused variables.

src/nsmenu.m

@@ -956,15 +956,12 @@ - (Lisp_Object)runMenuAt: (NSPoint)p forFrame: (struct frame *)f
   int i, k = 0;
   EmacsView *view = FRAME_NS_VIEW (f);
   EmacsToolbar *toolbar = [view toolbar];
-  int oldh;
 
   NSTRACE ("update_frame_tool_bar");
 
   if (view == nil || toolbar == nil) return;
   block_input ();
 
-  oldh = FRAME_TOOLBAR_HEIGHT (f);
-
 #ifdef NS_IMPL_COCOA
   [toolbar clearActive];
 #else

src/nsterm.h

@@ -705,7 +705,7 @@ typedef id instancetype;
 + (CGFloat)scrollerWidth;
 @end
 
-
+#ifdef NS_DRAW_TO_BUFFER
 @interface EmacsSurface : NSObject
 {
   NSMutableArray *cache;
@@ -722,6 +722,7 @@ typedef id instancetype;
 - (void) releaseContext;
 - (IOSurfaceRef) getSurface;
 @end
+#endif
 
 
 /* ==========================================================================

src/nsterm.m

@@ -5080,15 +5080,13 @@ in certain situations (rapid incoming events).
   id view;
   EmacsView *eview = FRAME_NS_VIEW (f);
   NSArray *subviews = [[eview superview] subviews];
-  BOOL removed = NO;
 
   NSTRACE ("ns_judge_scroll_bars");
   for (i = [subviews count]-1; i >= 0; --i)
     {
       view = [subviews objectAtIndex: i];
       if (![view isKindOfClass: [EmacsScroller class]]) continue;
-      if ([view judge])
-        removed = YES;
+      [view judge];
     }
 }