Drop old OpenBSD hack

[Jasper Lievisse Adriaanse <jasper@xxxxxxxxxxx>]

Hi,

There's no more need to add OpenBSD to the list of platforms not to define
_XOPEN_SOURCE_EXTENDED, zsh compiles just fine.

From 10b609dbb91f49d89d71bbe29212989607684a03 Mon Sep 17 00:00:00 2001
From: Jasper Lievisse Adriaanse <jasper@xxxxxxxxx>
Date: Thu, 17 Apr 2014 15:38:24 +0200
Subject: [PATCH] Remove OpenBSD from list of platforms where
 _XOPEN_SOURCE_EXTENDED shouldn't be defined

---
 configure.ac | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/configure.ac b/configure.ac
index 776b908..a2a6b9e 100644
--- a/configure.ac
+++ b/configure.ac
@@ -756,7 +756,7 @@ AH_TEMPLATE([ZSH_NO_XOPEN],
 AC_CACHE_CHECK(if _XOPEN_SOURCE_EXTENDED should not be defined,
 zsh_cv_no_xopen,
 [[case "$host_os" in
-  *openbsd*|*freebsd5*|*freebsd6.[012]*|*aix*)
+  *freebsd5*|*freebsd6.[012]*|*aix*)
   zsh_cv_no_xopen=yes
   ;;
   *)
-- 
1.9.1