Fix breakage in ARP code when IPV6 support not compiled in.

src/arp.c

@@ -44,6 +44,11 @@ static int filter_mac(int family, char *addrp, char *mac, size_t maclen, void *p
   if (maclen > DHCP_CHADDR_MAX)
     return 1;
 
+#ifndef HAVE_IPV6
+  if (family != AF_INET)
+    return 1;
+#endif
+
   /* Look for existing entry */
   for (arp = arps; arp; arp = arp->next)
     {

src/helper.c

@@ -300,7 +300,7 @@ int create_helper(int event_fd, int err_fd, uid_t uid, gid_t gid, long max_fd)
     
       if (!is6)
 	inet_ntop(AF_INET, &data.addr, daemon->addrbuff, ADDRSTRLEN);
-#ifdef HAVE_DHCP6
+#ifdef HAVE_IPV6
       else
 	inet_ntop(AF_INET6, &data.addr6, daemon->addrbuff, ADDRSTRLEN);
 #endif