Workaround for problems with tailcall optimisation and DTrace

sql/mysqld.cc

@@ -1764,9 +1764,13 @@ void close_connection(THD *thd, uint errcode, bool lock)
       net_send_error(thd, errcode, ER(errcode)); /* purecov: inspected */
     vio_close(vio);			/* vio is freed in delete thd */
   }
-  MYSQL_CONNECTION_DONE((int) errcode, thd->thread_id);
   if (lock)
     (void) pthread_mutex_unlock(&LOCK_thread_count);
+  MYSQL_CONNECTION_DONE((int) errcode, thd->thread_id);
+  if (MYSQL_CONNECTION_DONE_ENABLED())
+  {
+    sleep(0); /* Workaround to avoid tailcall optimisation */
+  }
   DBUG_VOID_RETURN;
 }
 #endif /* EMBEDDED_LIBRARY */