diff -ru zlib-1.2.5/gzlib.c zlib/gzlib.c
--- zlib-1.2.5/gzlib.c
+++ zlib/gzlib.c
@@ -5,7 +5,9 @@
 
 #include "gzguts.h"
 
-#if defined(_LARGEFILE64_SOURCE) && _LFS64_LARGEFILE-0
+#if defined(_WIN32)
+#  define LSEEK (z_off64_t)_lseeki64
+#elif defined(_LARGEFILE64_SOURCE) && _LFS64_LARGEFILE-0
 #  define LSEEK lseek64
 #else
 #  define LSEEK lseek
diff -ru zlib-1.2.5/mozzconf.h zlib/mozzconf.h
--- zlib-1.2.5/mozzconf.h	2011-12-15 18:10:49.000000000 +0800
+++ zlib/mozzconf.h	2011-12-16 16:08:00.000000000 +0800
@@ -0,0 +1,168 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* ***** BEGIN LICENSE BLOCK *****
+ * Version: MPL 1.1/GPL 2.0/LGPL 2.1
+ *
+ * The contents of this file are subject to the Mozilla Public License Version
+ * 1.1 (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ * http://www.mozilla.org/MPL/
+ *
+ * Software distributed under the License is distributed on an "AS IS" basis,
+ * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
+ * for the specific language governing rights and limitations under the
+ * License.
+ *
+ * The Original Code is the mozilla zlib configuration.
+ *
+ * The Initial Developer of the Original Code is IBM Corporation.
+ * Portions created by the Initial Developer are Copyright (C) 2004
+ * the Initial Developer. All Rights Reserved.
+ *
+ * Contributor(s):
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * either of the GNU General Public License Version 2 or later (the "GPL"),
+ * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
+ * in which case the provisions of the GPL or the LGPL are applicable instead
+ * of those above. If you wish to allow use of your version of this file only
+ * under the terms of either the GPL or the LGPL, and not to allow others to
+ * use your version of this file under the terms of the MPL, indicate your
+ * decision by deleting the provisions above and replace them with the notice
+ * and other provisions required by the GPL or the LGPL. If you do not delete
+ * the provisions above, a recipient may use your version of this file under
+ * the terms of any one of the MPL, the GPL or the LGPL.
+ *
+ * ***** END LICENSE BLOCK ***** */
+
+#ifndef MOZZCONF_H
+#define MOZZCONF_H
+
+#if defined(XP_WIN) && defined(ZLIB_DLL) && !defined(MOZ_ENABLE_LIBXUL)
+#undef ZLIB_DLL
+#endif
+
+#ifdef HAVE_VISIBILITY_ATTRIBUTE
+#define ZEXTERN __attribute__((visibility ("default"))) extern
+#endif
+
+/* Exported Symbols */
+#define zlibVersion MOZ_Z_zlibVersion
+#define deflate MOZ_Z_deflate
+#define deflateEnd MOZ_Z_deflateEnd
+#define inflate MOZ_Z_inflate
+#define inflateEnd MOZ_Z_inflateEnd
+#define deflateSetDictionary MOZ_Z_deflateSetDictionary
+#define deflateCopy MOZ_Z_deflateCopy
+#define deflateReset MOZ_Z_deflateReset
+#define deflateParams MOZ_Z_deflateParams
+#define deflateBound MOZ_Z_deflateBound
+#define deflatePrime MOZ_Z_deflatePrime
+#define inflateSetDictionary MOZ_Z_inflateSetDictionary
+#define inflateSync MOZ_Z_inflateSync
+#define inflateCopy MOZ_Z_inflateCopy
+#define inflateReset MOZ_Z_inflateReset
+#define inflateBack MOZ_Z_inflateBack
+#define inflateBackEnd MOZ_Z_inflateBackEnd
+#define zlibCompileFlags MOZ_Z_zlibCompileFlags
+#define compress MOZ_Z_compress
+#define compress2 MOZ_Z_compress2
+#define compressBound MOZ_Z_compressBound
+#define uncompress MOZ_Z_uncompress
+#define gzopen MOZ_Z_gzopen
+#define gzdopen MOZ_Z_gzdopen
+#define gzsetparams MOZ_Z_gzsetparams
+#define gzread MOZ_Z_gzread
+#define gzwrite MOZ_Z_gzwrite
+#define gzprintf MOZ_Z_gzprintf
+#define gzputs MOZ_Z_gzputs
+#define gzgets MOZ_Z_gzgets
+#define gzputc MOZ_Z_gzputc
+#define gzgetc MOZ_Z_gzgetc
+#define gzungetc MOZ_Z_gzungetc
+#define gzflush MOZ_Z_gzflush
+#define gzseek MOZ_Z_gzseek
+#define gzrewind MOZ_Z_gzrewind
+#define gztell MOZ_Z_gztell
+#define gzeof MOZ_Z_gzeof
+#define gzclose MOZ_Z_gzclose
+#define gzerror MOZ_Z_gzerror
+#define gzclearerr MOZ_Z_gzclearerr
+#define adler32 MOZ_Z_adler32
+#define crc32 MOZ_Z_crc32
+#define deflateInit_ MOZ_Z_deflateInit_
+#define deflateInit2_ MOZ_Z_deflateInit2_
+#define inflateInit_ MOZ_Z_inflateInit_
+#define inflateInit2_ MOZ_Z_inflateInit2_
+#define inflateBackInit_ MOZ_Z_inflateBackInit_
+#define inflateSyncPoint MOZ_Z_inflateSyncPoint
+#define get_crc_table MOZ_Z_get_crc_table
+#define zError MOZ_Z_zError
+
+/* Extra global symbols */
+#define _dist_code MOZ_Z__dist_code
+#define _length_code MOZ_Z__length_code
+#define _tr_align MOZ_Z__tr_align
+#define _tr_flush_block MOZ_Z__tr_flush_block
+#define _tr_init MOZ_Z__tr_init
+#define _tr_stored_block MOZ_Z__tr_stored_block
+#define _tr_tally MOZ_Z__tr_tally
+#define deflate_copyright MOZ_Z_deflate_copyright
+#define inflate_copyright MOZ_Z_inflate_copyright
+#define inflate_fast MOZ_Z_inflate_fast
+#define inflate_table MOZ_Z_inflate_table
+#define z_errmsg MOZ_Z_z_errmsg
+#define zcalloc MOZ_Z_zcalloc
+#define zcfree MOZ_Z_zcfree
+#define alloc_func MOZ_Z_alloc_func
+#define free_func MOZ_Z_free_func
+#define in_func MOZ_Z_in_func
+#define out_func MOZ_Z_out_func
+
+/* New as of libpng-1.2.3 */
+#define adler32_combine MOZ_Z_adler32_combine
+#define crc32_combine MOZ_Z_crc32_combine
+#define deflateSetHeader MOZ_Z_deflateSetHeader
+#define deflateTune MOZ_Z_deflateTune
+#define gzdirect MOZ_Z_gzdirect
+#define inflatePrime MOZ_Z_inflatePrime
+#define inflateGetHeader MOZ_Z_inflateGetHeader
+
+/* New as of zlib 1.2.5 */
+#define gzoffset MOZ_Z_gzoffset
+#define gzopen64 MOZ_Z_gzopen64
+#define gzseek64 MOZ_Z_gzseek64
+#define gztell64 MOZ_Z_gztell64
+#define gzoffset64 MOZ_Z_gzoffset64
+#define adler32_combine64 MOZ_Z_adler32_combine64
+#define crc32_combine64 MOZ_Z_crc32_combine64
+#define gz_error MOZ_Z_gz_error
+#define gz_intmax MOZ_Z_gz_intmax
+#define gz_strwinerror MOZ_Z_gz_strwinerror
+#define gzbuffer MOZ_Z_gzbuffer
+#define gzclose_r MOZ_Z_gzclose_r
+#define gzclose_w MOZ_Z_gzclose_w
+#define inflateMark MOZ_Z_inflateMark
+#define inflateReset2 MOZ_Z_inflateReset2
+#define inflateUndermine MOZ_Z_inflateUndermine
+#define charf MOZ_Z_charf
+#define gzFile MOZ_Z_gzFile
+#define gz_header MOZ_Z_gz_header
+#define gz_headerp MOZ_Z_gz_headerp
+#define intf MOZ_Z_intf
+#define uInt MOZ_Z_uInt
+#define uIntf MOZ_Z_uIntf
+#define uLong MOZ_Z_uLong
+#define uLongf MOZ_Z_uLongf
+#define voidp MOZ_Z_voidp
+#define voidpc MOZ_Z_voidpc
+#define voidpf MOZ_Z_voidpf
+#define gz_header_s MOZ_Z_gz_header_s
+#define internal_state MOZ_Z_internal_state
+
+/* Mangle Byte types except on Mac. */
+#if !defined(__MACTYPES__)
+#define Byte MOZ_Z_Byte
+#define Bytef MOZ_Z_Bytef
+#endif
+
+#endif
diff -ru zlib-1.2.5/zconf.h zlib/zconf.h
--- zlib-1.2.5/zconf.h	2010-04-19 01:58:06.000000000 +0800
+++ zlib/zconf.h	2011-12-14 08:06:37.000000000 +0800
@@ -8,6 +8,9 @@
 #ifndef ZCONF_H
 #define ZCONF_H
 
+/* This include does prefixing as below, but with an updated set of names */
+#include "mozzconf.h"
+
 /*
  * If you *really* need a unique prefix for all types and library functions,
  * compile with -DZ_PREFIX. The "standard" zlib should be compiled without it.
@@ -359,7 +359,7 @@ typedef uLong FAR uLongf;
    typedef Byte       *voidp;
 #endif
 
-#ifdef HAVE_UNISTD_H    /* may be set to #if 1 by ./configure */
+#if !defined(_WIN32)
 #  define Z_HAVE_UNISTD_H
 #endif
 
--- zlib-1.2.5/zlib.h	2010-04-20 12:12:48.000000000 +0800
+++ zlib/zlib.h	2013-04-06 16:08:48.000000000 +0800
@@ -1572,11 +1572,29 @@
 #endif
 
 #if !defined(ZLIB_INTERNAL) && _FILE_OFFSET_BITS-0 == 64 && _LFS64_LARGEFILE-0
+#  ifdef gzopen
+#    undef gzopen
+#  endif
 #  define gzopen gzopen64
+#  ifdef gzseek
+#    undef gzseek
+#  endif
 #  define gzseek gzseek64
+#  ifdef gztell
+#    undef gztell
+#  endif
 #  define gztell gztell64
+#  ifdef gzoffset
+#    undef gzoffset
+#  endif
 #  define gzoffset gzoffset64
+#  ifdef adler32_combine
+#    undef adler32_combine
+#  endif
 #  define adler32_combine adler32_combine64
+#  ifdef crc32_combine
+#    undef crc32_combine
+#  endif
 #  define crc32_combine crc32_combine64
 #  ifdef _LARGEFILE64_SOURCE
      ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *));