don't use arc4random_stir to seed

mail/exim/patches/patch-src_expand_c

@@ -0,0 +1,13 @@
+$OpenBSD: patch-src_expand_c,v 1.1 2013/10/22 08:46:10 sthen Exp $
+--- src/expand.c.orig	Tue Oct 22 02:27:08 2013
++++ src/expand.c	Tue Oct 22 02:27:51 2013
+@@ -822,8 +822,7 @@ vaguely_random_number(int max)
+ 
+ #ifdef HAVE_ARC4RANDOM
+       /* cryptographically strong randomness, common on *BSD platforms, not
+-      so much elsewhere.  Alas. */
+-      arc4random_stir();
++      so much elsewhere.  Alas.  Self-initializing, no need to seed. */
+ #elif defined(HAVE_SRANDOM) || defined(HAVE_SRANDOMDEV)
+ #ifdef HAVE_SRANDOMDEV
+       /* uses random(4) for seeding */