--- Net2/sys/wait.h	2018/04/24 18:03:58	1.1.1.1
+++ Net2/sys/wait.h	2018/04/24 18:16:38	1.1.1.2
@@ -30,9 +30,13 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- *	@(#)wait.h	7.17 (Berkeley) 6/19/91
+ *	from: @(#)wait.h	7.17 (Berkeley) 6/19/91
+ *	wait.h,v 1.3 1993/05/20 16:23:59 cgd Exp
  */
 
+#ifndef _SYS_WAIT_H_
+#define _SYS_WAIT_H_
+
 /*
  * This file holds definitions relevent to the wait4 system call
  * and the alternate interfaces that use it (wait, wait3, waitpid).
@@ -156,3 +160,5 @@ pid_t	wait4 __P((pid_t, int *, int, stru
 #endif
 __END_DECLS
 #endif
+
+#endif /* !_SYS_WAIT_H_ */