fix gcc warnings

Max Kellermann <max@duempel.org>
diff --git a/extensions/libipt_TTL.c b/extensions/libipt_TTL.c
index 4dfac06..b5a32c4 100644
--- a/extensions/libipt_TTL.c
+++ b/extensions/libipt_TTL.c
@@ -136,7 +136,7 @@
 	{ "ttl-set", 1, NULL, '1' },
 	{ "ttl-dec", 1, NULL, '2' },
 	{ "ttl-inc", 1, NULL, '3' },
-	{ }
+	{ .name = NULL }
 };
 
 static struct iptables_target ttl_target = {