zebra: use prototypes/includes in rt_netlink

Signed-off-by: David Lamparter <equinox@opensourcerouting.org>
diff --git a/zebra/rt_netlink.h b/zebra/rt_netlink.h
index 0facd49..d8f9db8 100644
--- a/zebra/rt_netlink.h
+++ b/zebra/rt_netlink.h
@@ -41,6 +41,9 @@
 nl_rtproto_to_str (u_char rtproto);
 
 
+extern int interface_lookup_netlink (void);
+extern int netlink_route_read (void);
+
 #endif /* HAVE_NETLINK */
 
 #endif /* _ZEBRA_RT_NETLINK_H */