Make GN write the platform for MSVS GYP files.

tools/gn/gyp_binary_target_writer.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/gyp_binary_target_writer.h"
 
 #include <set>
 
 #include "base/logging.h"
 #include "tools/gn/builder_record.h"
@@ skipping 144 matching lines @@
   }
 
   if (target_->hard_dep())
     Indent(indent) << "'hard_dependency': 1,\n";
 }
 
 void GypBinaryTargetWriter::WriteVCConfiguration(int indent) {
   Indent(indent) << "'configurations': {\n";
 
   Indent(indent + kExtraIndent) << "'Debug': {\n";
+  Indent(indent + kExtraIndent * 2) <<
+      "'msvs_configuration_platform': 'Win32',\n";
   Flags debug_flags(FlagsFromTarget(group_.debug->item()->AsTarget()));
   WriteVCFlags(debug_flags, indent + kExtraIndent * 2);
   Indent(indent + kExtraIndent) << "},\n";
 
   Indent(indent + kExtraIndent) << "'Release': {\n";
+  Indent(indent + kExtraIndent * 2) <<
+      "'msvs_configuration_platform': 'Win32',\n";
   Flags release_flags(FlagsFromTarget(group_.release->item()->AsTarget()));
   WriteVCFlags(release_flags, indent + kExtraIndent * 2);
   Indent(indent + kExtraIndent) << "},\n";
 
   // Note that we always need Debug_x64 and Release_x64 defined or GYP will get
   // confused, but we ca leave them empty if there's no 64-bit target.
   Indent(indent + kExtraIndent) << "'Debug_x64': {\n";
   if (group_.debug64) {
+    Indent(indent + kExtraIndent * 2) <<
+        "'msvs_configuration_platform': 'x64',\n";
     Flags flags(FlagsFromTarget(group_.debug64->item()->AsTarget()));
     WriteVCFlags(flags, indent + kExtraIndent * 2);
   }
   Indent(indent + kExtraIndent) << "},\n";
 
   Indent(indent + kExtraIndent) << "'Release_x64': {\n";
   if (group_.release64) {
+    Indent(indent + kExtraIndent * 2) <<
+        "'msvs_configuration_platform': 'x64',\n";
     Flags flags(FlagsFromTarget(group_.release64->item()->AsTarget()));
     WriteVCFlags(flags, indent + kExtraIndent * 2);
   }
   Indent(indent + kExtraIndent) << "},\n";
 
   Indent(indent) << "},\n";
 
   WriteSources(target_, indent);
   WriteDeps(target_, indent);
 }
@@ skipping 378 matching lines @@
     return;
 
   EscapeOptions options;
   options.mode = ESCAPE_JSON;
 
   Indent(indent) << "'" << name << "': [";
   WriteArrayValues(out_, values);
   out_ << " ],\n";
 }