more standardsier: cast to int to make sure we keep the negative numbers.

observed by jonas termansen

src/lib/libc/stdlib/mrand48.c

@@ -1,4 +1,4 @@
-/*	$OpenBSD: mrand48.c,v 1.4 2014/12/08 21:45:20 deraadt Exp $ */
+/*	$OpenBSD: mrand48.c,v 1.5 2014/12/09 00:02:18 tedu Exp $ */
 /*
  * Copyright (c) 1993 Martin Birgmeier
  * All rights reserved.
@@ -20,7 +20,7 @@ long
 mrand48(void)
 {
 	if (__rand48_deterministic == 0)
-		return arc4random();
+		return (int)arc4random();
 	__dorand48(__rand48_seed);
 	return ((long) __rand48_seed[2] << 16) + (long) __rand48_seed[1];
 }