XQuartz: Mark applicationWillTerminate: noreturn

X11Controller.m:938:1: warning: method 'applicationWillTerminate:' could be declared with attribute 'noreturn'
      [-Wmissing-noreturn,Semantic Issue]
{
^
Signed-off-by: Jeremy Huddleston Sequoia <jeremyhu@apple.com>

hw/xquartz/X11Controller.m

@@ -934,7 +934,7 @@ extern char *bundle_id_prefix;
             == NSAlertDefaultReturn) ? NSTerminateNow : NSTerminateCancel;
 }
 
-- (void) applicationWillTerminate:(NSNotification *)aNotification
+- (void) applicationWillTerminate:(NSNotification *)aNotification _X_NORETURN
 {
     int remain;
     [X11App prefs_synchronize];