gui/macosx: second attempt to fix equalizer issue #3718.

Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>
(cherry picked from commit 6a8df715f0f0831bab4e8344b7ff7b57d1c01964)
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

modules/gui/macosx/equalizer.m

@@ -296,7 +296,9 @@ static bool GetFiltersStatus( intf_thread_t *p_intf,
 
 - (IBAction)enable:(id)sender
 {
-    ChangeFiltersString( VLCIntf, (char *)"equalizer", [sender state] );
+//    ChangeFiltersString( VLCIntf, (char *)"equalizer", [sender state] );
+    // to fix #3718
+    aout_EnableFilter( pl_Get( VLCIntf ), (char *)"equalizer", [sender state]);
 }
 
 - (IBAction)preampSliderUpdated:(id)sender