Add support for 32-bit and 64-bit Windows compiles in GN.

tools/gn/args.cc

 // 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.
 
 #include "tools/gn/args.h"
 
 #include "build/build_config.h"
 #include "tools/gn/variables.h"
 
 #if defined(OS_WIN)
@@ skipping 161 matching lines @@
 #elif defined(OS_LINUX)
   os = "linux";
 #else
   #error Unknown OS type.
 #endif
   Value os_val(NULL, std::string(os));
   dest->SetValue(variables::kBuildOs, os_val, NULL);
   dest->SetValue(variables::kOs, os_val, NULL);
 
   // Host architecture.
-  static const char kIa32[] = "ia32";
-  static const char kIa64[] = "ia64";
+  static const char kX86[] = "x86";
+  static const char kX64[] = "x64";
   const char* arch = NULL;
 #if defined(OS_WIN)
   // ...on Windows, set the CPU architecture based on the underlying OS, not
   // whatever the current bit-tedness of the GN binary is.
   const base::win::OSInfo* os_info = base::win::OSInfo::GetInstance();
   switch (os_info->architecture()) {
     case base::win::OSInfo::X86_ARCHITECTURE:
-      arch = kIa32;
+      arch = kX86;
       break;
     case base::win::OSInfo::X64_ARCHITECTURE:
-      arch = kIa64;
+      arch = kX64;
       break;
     default:
       CHECK(false) << "Windows architecture not handled.";
       break;
   }
 #else
   // ...on all other platforms, just use the bit-tedness of the current
   // process.
   #if defined(ARCH_CPU_X86_64)
-    arch = kIa64;
+    arch = kX64;
   #elif defined(ARCH_CPU_X86)
-    arch = kIa32;
+    arch = kX86;
   #elif defined(ARCH_CPU_ARMEL)
     static const char kArm[] = "arm";
     arch = kArm;
   #else
     #error Unknown architecture.
   #endif
 #endif
   // Avoid unused var warning.
-  (void)kIa32;
-  (void)kIa64;
+  (void)kX86;
+  (void)kX64;
 
   Value arch_val(NULL, std::string(arch));
   dest->SetValue(variables::kBuildCpuArch, arch_val, NULL);
   dest->SetValue(variables::kCpuArch, arch_val, NULL);
 
   // Save the OS and architecture as build arguments that are implicitly
   // declared. This is so they can be overridden in a toolchain build args
   // override, and so that they will appear in the "gn args" output.
   //
   // Do not declare the build* variants since these shouldn't be changed.
@@ skipping 13 matching lines @@
        i != values.end(); ++i)
     scope->SetValue(i->first, i->second, i->second.origin());
 }
 
 void Args::SaveOverrideRecord(const Scope::KeyValueMap& values) const {
   base::AutoLock lock(lock_);
   for (Scope::KeyValueMap::const_iterator i = values.begin();
        i != values.end(); ++i)
     all_overrides_[i->first] = i->second;
 }