$NetBSD: patch-ab,v 1.4 2012/10/20 22:14:05 joerg Exp $

--- sem.c.orig	1994-10-04 16:44:53.000000000 +0000
+++ sem.c
@@ -27,13 +27,16 @@
  * semaphores */
 
 #include <stdio.h>
+#include <unistd.h>
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <sys/ipc.h>
 #include <sys/sem.h>
 #include <errno.h>
+#include <sys/param.h>
 
-#if defined(SYS5) || defined(ultrix) || defined(_AIX)
+#if defined(SYS5) || defined(ultrix) || defined(_AIX) \
+    || (defined(__NetBSD_Version__) && (__NetBSD_Version__ >= 104110000))
 union semun {
 	int val;
 	struct semid_ds *buf;
@@ -60,7 +63,6 @@ sem_set( sem_id, semn, val )
 	int val;
 {
 	union semun arg;
-	extern int errno;
 
 	arg.val = val;
 
@@ -94,7 +96,7 @@ new_sems( nsems )
 	return sem;
 }
 
-static
+static void
 do_sem( sem_id, pbuf, err )
 	int sem_id;
 	struct sembuf *pbuf;
@@ -148,10 +150,17 @@ void
 remove_sems( sem_id )
 	int sem_id;
 {
+#if defined(__NetBSD__) && defined(__NetBSD_Version__) \
+    && (__NetBSD_Version__ < 104110000)
+	union semun dummy;
+#else
+#define dummy NULL
+#endif
+
 	if( sem_id == -1 )
 		return;
 
-	if( semctl( sem_id, 0, IPC_RMID, NULL ) == -1 ){
+	if( semctl( sem_id, 0, IPC_RMID, dummy ) == -1 ){
 		report_proc();
 		perror( "internal error, failed to remove semaphore" );
 	}