macosx: compilation fix for llvm-gcc-4.2

modules/gui/macosx/MainWindow.h

@@ -139,6 +139,7 @@
 
     NSInteger i_originalLevel;
     NSRect previousSavedFrame;
+    BOOL b_video_view_was_hidden;
 }
 + (VLCMainWindow *)sharedInstance;
 

modules/gui/macosx/MainWindow.m

@@ -41,12 +41,6 @@
 #import <vlc_services_discovery.h>
 #import <vlc_aout_intf.h>
 
-@interface VLCMainWindow ()
-{
-    BOOL b_video_view_was_hidden;
-}
-@end
-
 @implementation VLCMainWindow
 static const float f_min_video_height = 70.0;