fix gcc warnings

Max Kellermann <max@duempel.org>
diff --git a/extensions/libipt_ttl.c b/extensions/libipt_ttl.c
index 622e60a..d7820f1 100644
--- a/extensions/libipt_ttl.c
+++ b/extensions/libipt_ttl.c
@@ -145,7 +145,7 @@
 	{ "ttl-eq", 1, NULL, '2'},
 	{ "ttl-lt", 1, NULL, '3'},
 	{ "ttl-gt", 1, NULL, '4'},
-	{ }
+	{ .name = NULL }
 };
 
 static struct iptables_match ttl_match = {