macosx: don't resize the vout in case VLC is in fullscreen mode (fixes #5920)

(cherry picked from commit 08159b75912049c454e8abd01d9be7873e494b35)
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

modules/gui/macosx/misc.h

@@ -77,6 +77,8 @@
 
 /* animate mode is only supported in >=10.4 */
 - (void)closeAndAnimate: (BOOL)animate;
+
+- (BOOL)isFullscreen;
 @end
 
 

modules/gui/macosx/misc.m

@@ -360,6 +360,11 @@ static NSMutableArray *blackoutWindows = NULL;
             [invoc invoke];
     }
 }
+
+- (BOOL)isFullscreen
+{
+    return YES;
+}
 @end
 
 /*****************************************************************************

modules/video_output/macosx.m

@@ -47,12 +47,9 @@
 #include <vlc_dialog.h>
 #include "opengl.h"
 
-#ifndef MAC_OS_X_VERSION_10_7
-enum {
-    NSApplicationPresentationFullScreen                 = (1 << 10),
-    NSApplicationPresentationAutoHideToolbar            = (1 << 11)
-};
-#endif
+@interface NSWindow (VLCCustomCode)
+- (BOOL)isFullscreen;
+@end
 
 /**
  * Forward declarations
@@ -496,7 +493,7 @@ static void OpenglSwap(vlc_gl_t *gl)
  */
 - (void)setWindowFrameWithValue:(NSValue *)value
 {
-    if (!(NSAppKitVersionNumber >= 1115.2 && [NSApp currentSystemPresentationOptions] == NSApplicationPresentationFullScreen))
+    if (![[self window] isFullscreen])
     {
         NSRect frame = [value rectValue];
         if (frame.origin.x <= 0.0 && frame.origin.y <= 0.0)