Restore @console handling and support for external getty

- Drop vhangup(), how did things ever work *with* this in?!
 - setsid() + TIOCSCTTY are best buds, see notty code
 - Allow storing any non-NULL string as tty->dev, expand in service_register()
 - Reorder parse_cmdline_args(), we need to expand @console to current dev
 - Fix tty arg parser, swapparoo for external getty
 - Refactor tty_atcon(), iterated over by service_register()
 - New arg format, need to translate for old run_getty2()

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>

src/svc.c

@@ -192,6 +192,8 @@ void svc_validate(svc_t *svc)
 	for (s = svc_iterator(&iter, 1); s; s = svc_iterator(&iter, 0)) {
 		char c[MAX_COND_LEN];
 
+		if (s->removed)
+			continue;
 		if (s == svc)
 			continue;