[client] ds: waitFrame now returns a bool to force rendering if needed

X11 needs to calibrate to get the best possible latency, as such it
needs the scene to render so that the render time of the scene can be
accounted for in the delay calculation.

client/src/main.c

@@ -171,14 +171,17 @@ static int renderThread(void * unused)
 
   while(g_state.state != APP_STATE_SHUTDOWN)
   {
+    bool forceRender = false;
+    if (g_state.jitRender)
+      forceRender = g_state.ds->waitFrame();
+
     app_handleRenderEvent(microtime());
     if (g_state.jitRender)
     {
-      g_state.ds->waitFrame();
-
       const uint64_t pending =
         atomic_load_explicit(&g_state.pendingCount, memory_order_acquire);
       if (!lgResetEvent(g_state.frameEvent)
+          && !forceRender
           && !pending
           && !app_overlayNeedsRender()
           && !g_state.lgr->needs_render(g_state.lgrData))