Drop Darwin patch in GNU patch

Seems to build fine without it.

http://hydra.nixos.org/build/3053575

pkgs/tools/text/gnupatch/darwin-fix.patch

@@ -1,60 +0,0 @@
-Fix builds on Darwin:
-http://lists.gnu.org/archive/html/bug-patch/2010-01/msg00004.html .
-
-
-commit 2c4e3ecddec8a686bd50d238f4cefebb950298b7
-Author: Andreas Gruenbacher <agruen@suse.de>
-Date:   Fri Jan 1 15:58:15 2010 +0100
-
-    * Makefile.in (LIBSRCS, LIBM4FILES): Add the missing files strnlen.c,
-    strnlen.m4, and safe-read.m4.
-
-diff --git a/Makefile.in b/Makefile.in
-index 3b3d78a..26dc281 100644
---- a/Makefile.in
-+++ b/Makefile.in
-@@ -91,6 +91,7 @@ LIBSRCS = \
- 	gl/lib/stripslash.c \
- 	gl/lib/strncasecmp.c \
- 	gl/lib/strndup.c \
-+	gl/lib/strnlen.c \
- 	gl/lib/xmalloc.c \
- 	gl/lib/xstrndup.c
-
-
-Add the missing bits from Gnulib.
-
---- /dev/null	2012-04-23 08:54:35.747205543 +0200
-+++ b/gl/lib/strnlen.c	2012-01-16 22:35:02.000000000 +0100
-@@ -0,0 +1,31 @@
-+/* Find the length of STRING, but scan at most MAXLEN characters.
-+   Copyright (C) 2005-2007, 2009-2012 Free Software Foundation, Inc.
-+   Written by Simon Josefsson.
-+
-+   This program is free software; you can redistribute it and/or modify
-+   it under the terms of the GNU General Public License as published by
-+   the Free Software Foundation; either version 2, or (at your option)
-+   any later version.
-+
-+   This program is distributed in the hope that it will be useful,
-+   but WITHOUT ANY WARRANTY; without even the implied warranty of
-+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-+   GNU General Public License for more details.
-+
-+   You should have received a copy of the GNU General Public License
-+   along with this program; if not, write to the Free Software Foundation,
-+   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
-+
-+#include <config.h>
-+
-+#include <string.h>
-+
-+/* Find the length of STRING, but scan at most MAXLEN characters.
-+   If no '\0' terminator is found in that many characters, return MAXLEN.  */
-+
-+size_t
-+strnlen (const char *string, size_t maxlen)
-+{
-+  const char *end = memchr (string, '\0', maxlen);
-+  return end ? (size_t) (end - string) : maxlen;
-+}

pkgs/tools/text/gnupatch/default.nix

@@ -8,8 +8,6 @@ stdenv.mkDerivation rec {
     sha256 = "0j10lq37ywcc4qiakan6wpm00abfrnnccq3ags129ad0z9b9zhjr";
   };
 
-  patches = stdenv.lib.optional stdenv.isDarwin ./darwin-fix.patch;
-
   buildInputs = stdenv.lib.optional doCheck ed;
 
   crossAttrs = {