Fix -fno-common build error. Taken from
https://svnweb.freebsd.org/ports?view=revision&revision=549579

Index: mdnsd/mdnsd.c
--- mdnsd/mdnsd.c.orig
+++ mdnsd/mdnsd.c
@@ -45,6 +45,8 @@ int		mdns_sock(void);
 void		fetchmyname(char [MAXHOSTNAMELEN]);
 void		fetchhinfo(struct hinfo *);
 
+ctl_conns_t	ctl_conns;
+
 struct mdnsd_conf	*conf = NULL;
 extern char		*malloc_options;
 
@@ -361,12 +363,12 @@ void
 imsg_event_add(struct imsgev *iev)
 {
 	if (iev->handler == NULL) {
-		imsg_flush(&iev->ibuf);
+		imsgbuf_flush(&iev->ibuf);
 		return;
 	}
 
 	iev->events = EV_READ;
-	if (iev->ibuf.w.queued)
+	if (imsgbuf_queuelen(&iev->ibuf) > 0)
 		iev->events |= EV_WRITE;
 
 	event_del(&iev->ev);
