Add OpenWRT ubus patch

Originally written by John Crispin <john@phrozen.org>
diff --git a/src/dnsmasq.h b/src/dnsmasq.h
index a7c3ea8..989a881 100644
--- a/src/dnsmasq.h
+++ b/src/dnsmasq.h
@@ -1445,6 +1445,13 @@
 #  endif
 #endif
 
+/* ubus.c */
+#ifdef HAVE_UBUS
+void set_ubus_listeners(void);
+void check_ubus_listeners(void);
+void ubus_event_bcast(const char *type, const char *mac, const char *ip, const char *name, const char *interface);
+#endif
+
 /* ipset.c */
 #ifdef HAVE_IPSET
 void ipset_init(void);