Accept packets with TTL=1

Packets with TTL=1 may be directed to local network (DHCP/DNS servers for example), so don't discard them
This is required by old versions of NetBSD which send DHCP DISCOVER packets with TTL=1
Signed-off-by: NHervé Poussineau <hpoussin@reactos.org>
Signed-off-by: NEdgar E. Iglesias <edgar.iglesias@gmail.com>

slirp/ip_input.c

@@ -144,7 +144,7 @@ ip_input(struct mbuf *m)
 	   m_adj(m, ip->ip_len - m->m_len);
 
 	/* check ip_ttl for a correct ICMP reply */
-	if(ip->ip_ttl==0 || ip->ip_ttl==1) {
+	if(ip->ip_ttl==0) {
 	  icmp_error(m, ICMP_TIMXCEED,ICMP_TIMXCEED_INTRANS, 0,"ttl");
 	  goto bad;
 	}