use var_ToggleBool when applicable.

modules/video_output/msw/events.c

@@ -774,13 +774,10 @@ static long FAR PASCAL DirectXEventProc( HWND hwnd, UINT message,
         {
             case IDM_TOGGLE_ON_TOP:            /* toggle the "on top" status */
             {
-                vlc_value_t val;
                 msg_Dbg( p_vout, "WinProc WM_SYSCOMMAND: IDM_TOGGLE_ON_TOP");
 
                 /* Change the current value */
-                var_Get( p_vout, "video-on-top", &val );
-                val.b_bool = !val.b_bool;
-                var_Set( p_vout, "video-on-top", val );
+                var_ToggleBool( p_vout, "video-on-top" );
                 return 0;
             }
         }

modules/video_output/x11/xcommon.c

@@ -1121,9 +1121,7 @@ static int ManageVideo( vout_thread_t *p_vout )
                         val.i_int &= ~2;
                         var_Set( p_vout, "mouse-button-down", val );
 
-                        var_Get( p_vout->p_libvlc, "intf-show", &val );
-                        val.b_bool = !val.b_bool;
-                        var_Set( p_vout->p_libvlc, "intf-show", val );
+                        var_ToggleBool( p_vout->p_libvlc, "intf-show" );
                     }
                     break;