Added #include <linux/stddef.h> for offsetof().
diff --git a/extensions/libipt_limit.c b/extensions/libipt_limit.c
index 822109b..24875ef 100644
--- a/extensions/libipt_limit.c
+++ b/extensions/libipt_limit.c
@@ -8,6 +8,7 @@
 #include <stdlib.h>
 #include <getopt.h>
 #include <iptables.h>
+#include <linux/stddef.h>
 #include <linux/netfilter_ipv4/ip_tables.h>
 #include <linux/netfilter_ipv4/ipt_limit.h>