diff --git a/lib/libc/compat/sys/Makefile.inc b/lib/libc/compat/sys/Makefile.inc
index 75d1c3c25cde..1803614c6b7e 100644
--- a/lib/libc/compat/sys/Makefile.inc
+++ b/lib/libc/compat/sys/Makefile.inc
@@ -1,11 +1,12 @@
-#	$NetBSD: Makefile.inc,v 1.6 2006/07/31 16:34:42 martin Exp $
+#	$NetBSD: Makefile.inc,v 1.7 2007/07/14 15:53:04 dsl Exp $
 
 .PATH: ${COMPATDIR}/sys
 SRCS+= compat_getdents.c compat_getdirentries.c compat_msync.c \
     compat_ntp_gettime.c \
     compat_semctl.c compat_sigaltstack.c compat_stat.c compat___stat13.c \
     compat_statfs.c compat_socket.c compat_getfh.c \
-    compat_fhopen.c compat___fhstat30.c compat_fhstatvfs.c compat_fhstatvfs1.c
+    compat_fhopen.c compat___fhstat30.c compat_fhstatvfs.c compat_fhstatvfs1.c \
+    compat_mount.c
 MAN+=	getdirentries.3
 
 .if ${MKLINT} != "no"
diff --git a/lib/libc/compat/sys/compat_mount.c b/lib/libc/compat/sys/compat_mount.c
new file mode 100644
index 000000000000..658665c8fa84
--- /dev/null
+++ b/lib/libc/compat/sys/compat_mount.c
@@ -0,0 +1,28 @@
+/*	$NetBSD: compat_mount.c,v 1.1 2007/07/14 15:53:04 dsl Exp $	*/
+
+
+#include <sys/cdefs.h>
+#if defined(LIBC_SCCS) && !defined(lint)
+__RCSID("$NetBSD: compat_mount.c,v 1.1 2007/07/14 15:53:04 dsl Exp $");
+#endif /* LIBC_SCCS and not lint */
+
+#define __LIBC12_SOURCE__
+
+#include <sys/types.h>
+#include <sys/mount.h>
+
+__warn_references(mount,
+    "warning: reference to compatibility mount(); include <sys/mount.h> to generate correct reference")
+
+int	mount(const char *, const char *, int, void *);
+int	__mount50(const char *, const char *, int, void *, size_t);
+
+/*
+ * Convert old mount() call to new calling convention
+ * The kernel will treat length 0 as 'default for the fs'.
+ */
+int
+mount(const char *type, const char *dir, int flags, void *data)
+{
+	return __mount50(type, dir, flags, data, 0);
+}
diff --git a/lib/libc/sys/Makefile.inc b/lib/libc/sys/Makefile.inc
index d70168d1a8c0..2a5daf5adb0e 100644
--- a/lib/libc/sys/Makefile.inc
+++ b/lib/libc/sys/Makefile.inc
@@ -1,4 +1,4 @@
-#	$NetBSD: Makefile.inc,v 1.174 2007/06/03 17:35:24 christos Exp $
+#	$NetBSD: Makefile.inc,v 1.175 2007/07/14 15:53:04 dsl Exp $
 #	@(#)Makefile.inc	8.3 (Berkeley) 10/24/94
 
 # sys sources
@@ -74,8 +74,8 @@ ASM=	access.S acct.S \
 		_lwp_suspend.S _lwp_continue.S _lwp_wakeup.S _lwp_detach.S \
 		_lwp_getprivate.S _lwp_setprivate.S \
 	madvise.S mincore.S minherit.S mkdir.S mkfifo.S mknod.S \
-		mlock.S mlockall.S mount.S mprotect.S __msgctl13.S msgget.S \
-		munlock.S munlockall.S munmap.S \
+		mlock.S mlockall.S __mount50.S mprotect.S __msgctl13.S \
+		msgget.S munlock.S munlockall.S munmap.S \
 	nfssvc.S __ntp_gettime30.S \
 	pathconf.S pmc_get_info.S pmc_control.S __posix_chown.S \
 		posix_fadvise.S \