Include ttymsg.h from ../../usr.bin/wall instead of rolling our own

prototype.

libexec/talkd/Makefile

@@ -2,6 +2,7 @@
 # $FreeBSD$
 
 PROG=	ntalkd
+CFLAGS+=-I${.CURDIR}/../../usr.bin/wall
 SRCS=	talkd.c announce.c process.c table.c print.c ttymsg.c
 .PATH:  ${.CURDIR}/../../usr.bin/wall
 MAN=	talkd.8

libexec/talkd/announce.c

@@ -57,10 +57,11 @@ static const char rcsid[] =
 #include <unistd.h>
 #include <vis.h>
 
+#include "ttymsg.h"
+
 extern char hostname[];
 
 int print_mesg __P((char *, FILE *, CTL_MSG *, char *));
-char *ttymsg __P((struct iovec *, int, char *, int));
 
 /*
  * Announce an invitation to talk.