Check for new SLAAC addresses when we add new prefixes.

src/dnsmasq.h

@@ -1047,6 +1047,7 @@ void lease6_filter(int lease_type, int iaid, struct dhcp_context *context);
 struct dhcp_lease *lease6_find_by_addr(struct in6_addr *net, int prefix, u64 addr);
 u64 lease_find_max_addr6(struct dhcp_context *context);
 void lease_ping_reply(struct in6_addr *sender, unsigned char *packet, char *interface);
+void lease_update_slaac(time_t now);
 #endif
 void lease_set_hwaddr(struct dhcp_lease *lease, unsigned char *hwaddr,
 		      unsigned char *clid, int hw_len, int hw_type, int clid_len, time_t now, int force);