The PANE_REDRAW flag bit might be needed by other panes so we can't

clear it on the first redraw, and it can't be set when we are finished
or they would be redrawn again, so if the redraw is deferred for a
client, copy the redraw flag into a separate set of bits just for that
client.

tmux.h

@@ -1562,6 +1562,8 @@ struct client {
 	int		 flags;
 	struct key_table *keytable;
 
+	uint64_t	 redraw_panes;
+
 	char		*message_string;
 	struct event	 message_timer;
 	u_int		 message_next;