ui/clipboard: add a clipboard reset serial event

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
diff --git a/ui/cocoa.m b/ui/cocoa.m
index 6640a2e..7ca429f 100644
--- a/ui/cocoa.m
+++ b/ui/cocoa.m
@@ -1837,6 +1837,9 @@
     case QEMU_CLIPBOARD_UPDATE_INFO:
         cocoa_clipboard_update_info(notify->info);
         return;
+    case QEMU_CLIPBOARD_RESET_SERIAL:
+        /* ignore */
+        return;
     }
 }