Always build our own zlib.

gyp/zlib.gyp

 # Copyright 2014 Google Inc.
 #
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 {
   'variables': {
     'skia_warnings_as_errors': 0,
   },
   'targets': [
   {
-    # Only used by win, down below.
-    'target_name' : 'zlib_x86_simd',
-    'type': 'static_library',
-    'cflags' : ['-msse4.2', '-mpclmul'],
-    'sources' : [
-      '../third_party/externals/zlib/crc_folding.c',
-      '../third_party/externals/zlib/fill_window_sse.c',
-    ],
+      'target_name': 'zlib',
       'conditions': [
-        ['skia_clang_build==1', {
-          'msvs_settings': {
-            'VCCLCompilerTool': {
-              'AdditionalOptions': [ '-msse4.2', '-mpclmul' ],
-            },
+        [ 'skia_android_framework', {
+          'type': 'none',
+          'direct_dependent_settings': {
+              'include_dirs': [ 'external/zlib' ],
+              'link_settings': { 'libraries': [ '-lz' ] },
           },
-        }],
-      ],
-  },
-  {
-      'target_name': 'zlib',
-      'direct_dependent_settings': {
-        'conditions': [
-          [ 'skia_android_framework', { 'include_dirs': [ 'external/zlib' ] }],
-          [ 'skia_os == "mac" or skia_os == "ios"', {
-              # XCode needs a full library name, not -lz.
-              'link_settings': { 'libraries': [ 'libz.dylib' ] },
-          }],
-          [ 'skia_os not in ["mac", "ios", "win"]',{
-              'link_settings': { 'libraries': [ '-lz' ] },
-          }]
-        ],
-      },
-      'conditions': [
-        [ 'skia_os != "win"', {
-          'type': 'none',
         }, {
-          # win
           'type': 'static_library',
           'sources': [
             '../third_party/externals/zlib/adler32.c',
             '../third_party/externals/zlib/compress.c',
             '../third_party/externals/zlib/crc32.c',
-            '../third_party/externals/zlib/crc32.h',
             '../third_party/externals/zlib/deflate.c',
-            '../third_party/externals/zlib/deflate.h',
             '../third_party/externals/zlib/gzclose.c',
-            '../third_party/externals/zlib/gzguts.h',
             '../third_party/externals/zlib/gzlib.c',
             '../third_party/externals/zlib/gzread.c',
             '../third_party/externals/zlib/gzwrite.c',
             '../third_party/externals/zlib/infback.c',
             '../third_party/externals/zlib/inffast.c',
-            '../third_party/externals/zlib/inffast.h',
-            '../third_party/externals/zlib/inffixed.h',
             '../third_party/externals/zlib/inflate.c',
-            '../third_party/externals/zlib/inflate.h',
             '../third_party/externals/zlib/inftrees.c',
-            '../third_party/externals/zlib/inftrees.h',
-            '../third_party/externals/zlib/mozzconf.h',
+            '../third_party/externals/zlib/simd_stub.c',
             '../third_party/externals/zlib/trees.c',
-            '../third_party/externals/zlib/trees.h',
             '../third_party/externals/zlib/uncompr.c',
-            '../third_party/externals/zlib/x86.h',
-            '../third_party/externals/zlib/x86.c',
-            '../third_party/externals/zlib/zconf.h',
-            '../third_party/externals/zlib/zlib.h',
             '../third_party/externals/zlib/zutil.c',
-            '../third_party/externals/zlib/zutil.h',
           ],
           'include_dirs': [
             '../third_party/externals/zlib/',
           ],
           'direct_dependent_settings': {
             'include_dirs': [
               '../third_party/externals/zlib',
             ],
           },
-          'dependencies': [
-            'zlib_x86_simd',
-          ],
           'defines': [
             '_CRT_NONSTDC_NO_DEPRECATE',
           ],
         }],
       ],
   }],
 }