In-House patch. Submitted to upstream, but not accepted yet.
Added errno.h to remove compile error of defininig extern int errno without including errno.h.

--- tmux-1.8/server-client.c.orig	2013-08-13 12:42:15.161702456 -0700
+++ tmux-1.8/server-client.c	2013-08-13 12:44:32.917403564 -0700
@@ -25,6 +25,7 @@
 #include <string.h>
 #include <time.h>
 #include <unistd.h>
+#include <errno.h>
 
 #include "tmux.h"