$OpenBSD: patch-src_openvpn_syshead_h,v 1.1 2013/04/20 16:22:55 sthen Exp $
--- src/openvpn/syshead.h.orig	Thu Nov 22 13:07:51 2012
+++ src/openvpn/syshead.h	Thu Mar  7 14:02:35 2013
@@ -29,7 +29,7 @@
 #include "compat-stdbool.h"
 
 /* branch prediction hints */
-#if defined(__GNUC__)
+#if defined(__GNUC__) && __GNUC__ >= 3
 # define likely(x)       __builtin_expect((x),1)
 # define unlikely(x)     __builtin_expect((x),0)
 #else
