--- Net2/netinet/tcp_debug.h	2018/04/24 18:03:54	1.1
+++ Net2/netinet/tcp_debug.h	2018/04/24 18:13:34	1.1.1.2
@@ -30,9 +30,13 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- *	@(#)tcp_debug.h	7.4 (Berkeley) 6/28/90
+ *	from: @(#)tcp_debug.h	7.4 (Berkeley) 6/28/90
+ *	tcp_debug.h,v 1.3 1993/05/20 03:50:33 cgd Exp
  */
 
+#ifndef _NETINET_TCP_DEBUG_H_
+#define _NETINET_TCP_DEBUG_H_
+
 struct	tcp_debug {
 	n_time	td_time;
 	short	td_act;
@@ -57,3 +61,5 @@ char	*tanames[] =
 #define	TCP_NDEBUG 100
 struct	tcp_debug tcp_debug[TCP_NDEBUG];
 int	tcp_debx;
+
+#endif /* !_NETINET_TCP_DEBUG_H_ */