If no target client is specified to commands which accept one, try to guess the

current client, in a similar manner to how sessions already work: if the
current session can be established and has only one client, use that; otherwise
use the most recently created client.

tmux.h

@@ -922,6 +922,7 @@ struct tty_ctx {
 /* Client connection. */
 struct client {
 	struct imsgbuf	 ibuf;
+	struct timeval	 tv;
 
 	struct environ	 environ;