Make sure the window is drawn when Fl_X::make() is called

(necessary with Mac OS 10.11).

git-svn-id: file:///fltk/svn/fltk/branches/branch-1.3@10800 ea41ed52-d2ee-0310-a9c1-e6b18d33e121

src/Fl_cocoa.mm

@@ -3039,6 +3039,7 @@ void Fl_X::make(Fl_Window* w)
     x->changed_resolution(false);
 #endif
     [cw makeKeyAndOrderFront:nil];
+    [cw displayIfNeeded]; // make sure the window is drawn (useful with 10.11)
   }
   
   if (!w->parent()) {