dix: Remove clients from input and output ready queues after closing

Delay removing the client from these two queues until all potential
I/O has completed in case we mark the client as ready for reading or
with pending output during the close operation.

Bugzilla: https://bugs.freedesktop.org/100957
Signed-off-by: Keith Packard <keithp@keithp.com>
Tested-by: Nick Sarnie <commendsarnex@gmail.com>
Reviewed-by: Michel Dänzer <michel.daenzer@amd.com>

dix/dispatch.c

@@ -3414,7 +3414,6 @@ CloseDownClient(ClientPtr client)
         if (grabState != GrabNone && grabClient == client) {
             UngrabServer(client);
         }
-        mark_client_not_ready(client);
         BITCLEAR(grabWaiters, client->index);
         DeleteClientFromAnySelections(client);
         ReleaseActiveGrabs(client);
@@ -3443,8 +3442,9 @@ CloseDownClient(ClientPtr client)
         if (ClientIsAsleep(client))
             ClientSignal(client);
         ProcessWorkQueueZombies();
-        output_pending_clear(client);
         CloseDownConnection(client);
+        output_pending_clear(client);
+        mark_client_not_ready(client);
 
         /* If the client made it to the Running stage, nClients has
          * been incremented on its behalf, so we need to decrement it