Index: head/sys/sys/msg.h
===================================================================
--- head/sys/sys/msg.h
+++ head/sys/sys/msg.h
@@ -163,8 +163,9 @@
 	struct	ucred *cred;	/* creator's credentials */
 };
 
-#else /* !_KERNEL */
+#endif /* _KERNEL */
 
+#if !defined(_KERNEL) || defined(_WANT_MSG_PROTOTYPES)
 __BEGIN_DECLS
 int msgctl(int, int, struct msqid_ds *);
 int msgget(key_t, int);
@@ -176,6 +177,6 @@
 #endif
 __END_DECLS
 
-#endif /* _KERNEL */
+#endif /* !_KERNEL || _WANT_MSG_PROTOTYPES  */
 
 #endif /* !_SYS_MSG_H_ */
Index: head/sys/sys/sem.h
===================================================================
--- head/sys/sys/sem.h
+++ head/sys/sys/sem.h
@@ -137,8 +137,9 @@
  */
 void	semexit(struct proc *p);
 
-#else /* ! _KERNEL */
+#endif /* _KERNEL */
 
+#if !defined(_KERNEL) || defined(_WANT_SEM_PROTOTYPES)
 __BEGIN_DECLS
 #if __BSD_VISIBLE
 int semsys(int, ...);
@@ -148,6 +149,6 @@
 int semop(int, struct sembuf *, size_t);
 __END_DECLS
 
-#endif /* !_KERNEL */
+#endif /* !_KERNEL || _WANT_SEM_PROTOTYPES */
 
 #endif /* !_SYS_SEM_H_ */
Index: head/sys/sys/shm.h
===================================================================
--- head/sys/sys/shm.h
+++ head/sys/sys/shm.h
@@ -144,8 +144,9 @@
 
 void	shmexit(struct vmspace *);
 void	shmfork(struct proc *, struct proc *);
-#else /* !_KERNEL */
+#endif /* _KERNEL */
 
+#if !defined(_KERNEL) || defined(_WANT_SHM_PROTOTYPES)
 #include <sys/cdefs.h>
 
 #ifndef _SIZE_T_DECLARED
@@ -163,6 +164,6 @@
 int shmdt(const void *);
 __END_DECLS
 
-#endif /* !_KERNEL */
+#endif /* _KERNEL || _WANT_SHM_PROTOTYPES */
 
 #endif /* !_SYS_SHM_H_ */
Index: head/usr.bin/ipcrm/ipcrm.c
===================================================================
--- head/usr.bin/ipcrm/ipcrm.c
+++ head/usr.bin/ipcrm/ipcrm.c
@@ -34,6 +34,9 @@
 __FBSDID("$FreeBSD$");
 
 #include <sys/param.h>
+#define _WANT_MSG_PROTOTYPES
+#define _WANT_SEM_PROTOTYPES
+#define _WANT_SHM_PROTOTYPES
 #define _KERNEL
 #include <sys/sem.h>
 #include <sys/shm.h>