diff --git a/games/hack/hack.mklev.c b/games/hack/hack.mklev.c
index 236f83268e2..3217923d274 100644
--- a/games/hack/hack.mklev.c
+++ b/games/hack/hack.mklev.c
@@ -1,9 +1,11 @@
 /* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
 /* hack.mklev.c - version 1.0.3 */
 
+#include <stdlib.h>
+#include <unistd.h>
+
 #include "hack.h"
 
-extern char *getlogin(), *getenv();
 extern struct monst *makemon();
 extern struct obj *mkobj_at();
 extern struct trap *maketrap();
diff --git a/games/hack/hack.unix.c b/games/hack/hack.unix.c
index 88e743f9551..88ebdd606b0 100644
--- a/games/hack/hack.unix.c
+++ b/games/hack/hack.unix.c
@@ -14,22 +14,16 @@
 
 #include <stdio.h>
 #include <errno.h>
+#include <stdlib.h>
 #include "hack.h"	/* mainly for index() which depends on BSD */
 
 #include	<sys/types.h>		/* for time_t and stat */
 #include	<sys/stat.h>
-#ifdef BSD
-#include	<sys/time.h>
-#else
 #include	<time.h>
-#endif BSD
-
-extern char *getenv();
-extern time_t time();
 
 setrandom()
 {
- 	(void) srandom((int) time ((time_t *) 0));
+	(void) srandomdev();
 }
 
 struct tm *
diff --git a/games/hack/rnd.c b/games/hack/rnd.c
index 8547cef210a..022cf691014 100644
--- a/games/hack/rnd.c
+++ b/games/hack/rnd.c
@@ -1,6 +1,8 @@
 /* rnd.c - version 1.0.2 */
 
-#define RND(x)	((random()>>3) % x)
+#include <stdlib.h>
+
+#define RND(x)  (random() % x)
 
 rn1(x,y)
 register x,y;