Make *some* version of the Win GN build work.

third_party/zlib/BUILD.gn

 # Copyright (c) 2013 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 config("zlib_config") {
   include_dirs = [ "." ]
 }
 
 static_library("zlib_x86_simd") {
-  if (cpu_arch == "x86" || cpu_arch == "x64") {
+  if (!is_win && (cpu_arch == "x86" || cpu_arch == "x64")) {

[Nico, 2014/11/18 19:13:43]

This isn't correct. The gyp version does use crc_folder.c and fill_window_sse.c
on Windows, it just doesn't need the -msse4.2 flags and whatnot.

[Dirk Pranke, 2014/11/18 20:37:45]

Okay, good to know. I'll try to fix that in a follow up patch.

I fully expect many of these initial patches to be wrong in some dimension;
often we're just trying to get things to compile *at all*, and we'll have to go
and patch things later.

This is not to say that we shouldn't try to get things right from the start,
just that we won't always be successful.

     sources = [ "crc_folding.c", "fill_window_sse.c" ]
     cflags = [ "-msse2", "-msse4.2", "-mpclmul" ]
   } else {
     sources = [ "simd_stub.c"]
+    if (is_win) {
+      # TODO(GYP): crbug.com/431462 disable warning about structure padding.
+      cflags = [ "/wd4324" ]
+    }
   }
 }
 
 static_library("zlib") {
   if (!is_win) {
     # Don't stomp on "libzlib" on other platforms.
     output_name = "chrome_zlib"
   }
 
   sources = [
@@ skipping 20 matching lines @@
     "trees.c",
     "trees.h",
     "uncompr.c",
     "x86.h",
     "zconf.h",
     "zlib.h",
     "zutil.c",
     "zutil.h",
   ]
 
-  if (cpu_arch == "x86" || cpu_arch == "x64") {
+  if (!is_win && (cpu_arch == "x86" || cpu_arch == "x64")) {
     sources += [ "x86.c" ]
   }
 
   configs -= [ "//build/config/compiler:chromium_code" ]
   configs += [ "//build/config/compiler:no_chromium_code" ]
 
   public_configs = [ ":zlib_config" ]
   deps = [ ":zlib_x86_simd" ]
 }
 
@@ skipping 40 matching lines @@
     "google/zip_internal.cc",
     "google/zip_internal.h",
     "google/zip_reader.cc",
     "google/zip_reader.h",
   ]
   deps = [
     ":minizip",
     "//base",
   ]
 }