Add set_visible() for GL windows on Mac OS X (STR #1707)

git-svn-id: file:///fltk/svn/fltk/branches/branch-1.1@5997 ea41ed52-d2ee-0310-a9c1-e6b18d33e121

CHANGES

@@ -4,6 +4,8 @@ CHANGES IN FLTK 1.1.8
 	  STR #1457, STR #1458, STR #1460, STR #1481, STR #1578,
 	  STR #1639, STR #1645, STR #1644, STR #1792, STR #1793,
 	  STR #1742, STR #1777, STR #1794, STR #1827, STR #1843)
+	- Fl_Gl_Window::show() did not work reliably on Mac OS X
+	  (STR #1707)
 	- Added Fl_Group::clip_children() methods to support
 	  automatic clipping of child widget drawing (STR #1844)
 	- Fl_Browser_ and friends now support FL_WHEN_ENTER_KEY

src/Fl_Gl_Window.cxx

@@ -84,6 +84,10 @@ void Fl_Gl_Window::show() {
 #endif
   }
   Fl_Window::show();
+
+#ifdef __APPLE__
+  set_visible();
+#endif /* __APPLE__ */
 }
 
 void Fl_Gl_Window::invalidate() {