OpenBSD does not need nor provide arc4random_(addrandom|stir)
--- src/lib/arc4random.h.orig	Sun Sep 11 16:28:28 2011
+++ src/lib/arc4random.h	Tue Oct 22 19:04:07 2013
@@ -37,9 +37,21 @@
 #include "common.h"
 
 #ifndef HAS_ARC4RANDOM
+
 guint32 arc4random(void);
 void arc4random_stir(void);
 void arc4random_addrandom(const unsigned char *dat, int datlen);
+
+#else
+
+#ifndef HAS_ARC4RANDOM_ADDRANDOM
+#define arc4random_addrandom(a, b)
+#endif
+
+#ifndef HAS_ARC4RANDOM_STIR
+#define arc4random_stir()
+#endif
+
 #endif
 
 #endif /* _arc4random_h_ */