diff --git a/sys/mac/macunix.c b/sys/mac/macunix.c
new file mode 100644
index 000000000..e4c6900f4
--- /dev/null
+++ b/sys/mac/macunix.c
@@ -0,0 +1,55 @@
+/*	SCCS Id: @(#)macunix.c	3.1	94/11/07	*/
+/* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
+/* NetHack may be freely redistributed.  See license for details. */
+
+/* This file collects some Unix dependencies */
+
+#include "hack.h"
+
+#ifndef __MWERKS__
+#include <fcntl.h>
+#endif
+
+
+#if 0
+int
+uptodate(int fd)
+#if defined(applec) || defined(__MWERKS__)
+# pragma unused(fd)
+#endif
+	return(1);
+}
+#endif
+
+
+void
+regularize(char *s)
+{
+	register char *lp;
+
+	for (lp = s; *lp; lp++) {
+		if (*lp == '.' || *lp == ':')
+			*lp = '_';
+	}
+}
+
+
+void
+getlock(void)
+{
+	int fd;
+	int pid = getpid(); /* Process Serial Number ? */
+	
+	set_levelfile_name (lock, 0);
+
+	if ((fd = open (lock, O_RDWR | O_EXCL | O_CREAT, LEVL_TYPE)) == -1) {
+		raw_printf ("Could not lock the game %s.", lock);
+		panic ("Another game in progress?");
+	}
+
+	if (write (fd, (char *)&pid, sizeof (pid)) != sizeof (pid))  {
+		raw_printf ("Could not lock the game %s.", lock);
+		panic("Disk locked?");
+	}
+	close (fd);
+}