netfilter: correct CHECKSUM header and export it

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Patrick McHardy <kaber@trash.net>

include/linux/netfilter/Kbuild

@@ -3,6 +3,7 @@ header-y += nf_conntrack_tuple_common.h
 header-y += nfnetlink_conntrack.h
 header-y += nfnetlink_log.h
 header-y += nfnetlink_queue.h
+header-y += xt_CHECKSUM.h
 header-y += xt_CLASSIFY.h
 header-y += xt_CONNMARK.h
 header-y += xt_CONNSECMARK.h

include/linux/netfilter/xt_CHECKSUM.h

@@ -6,8 +6,10 @@
  *
  * This software is distributed under GNU GPL v2, 1991
 */
-#ifndef _IPT_CHECKSUM_TARGET_H
-#define _IPT_CHECKSUM_TARGET_H
+#ifndef _XT_CHECKSUM_TARGET_H
+#define _XT_CHECKSUM_TARGET_H
+
+#include <linux/types.h>
 
 #define XT_CHECKSUM_OP_FILL	0x01	/* fill in checksum in IP header */
 
@@ -15,4 +17,4 @@ struct xt_CHECKSUM_info {
 	__u8 operation;	/* bitset of operations */
 };
 
-#endif /* _IPT_CHECKSUM_TARGET_H */
+#endif /* _XT_CHECKSUM_TARGET_H */