New timing infrastructure. There's a new function schedule_timer()

which pretty much any module can call to request a call-back in the
future. So terminal.c can do its own handling of blinking, visual
bells and deferred screen updates, without having to rely on
term_update() being called 50 times a second (fixes: pterm-timer);
and ssh.c and telnet.c both invoke a new module pinger.c which takes
care of sending keepalives, so they get sent uniformly in all front
ends (fixes: plink-keepalives, unix-keepalives).

[originally from svn r4906]
[this svn revision also touched putty-wishlist]

unix/uxcons.c

@@ -35,6 +35,14 @@ void update_specials_menu(void *frontend)
 {
 }
 
+void notify_remote_exit(void *frontend)
+{
+}
+
+void timer_change_notify(long next)
+{
+}
+
 void verify_ssh_host_key(void *frontend, char *host, int port, char *keytype,
 			 char *keystr, char *fingerprint)
 {