Add support for the IFF_ECHO flag
diff --git a/lib/route/link.c b/lib/route/link.c
index 2953999..2fec334 100644
--- a/lib/route/link.c
+++ b/lib/route/link.c
@@ -1035,6 +1035,7 @@
 	__ADD(IFF_RUNNING, running)
 	__ADD(IFF_LOWER_UP, lowerup)
 	__ADD(IFF_DORMANT, dormant)
+	__ADD(IFF_ECHO, echo)
 };
 
 char * rtnl_link_flags2str(int flags, char *buf, size_t len)