GN Mac build work

tools/gn/gyp_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_target_writer.h"
 
 #include <iostream>
 
 #include "base/file_util.h"
 #include "base/files/file_path.h"
@@ skipping 19 matching lines @@
                                 Err* err) {
   if (targets.empty())
     return;
   const BuildSettings* debug_build_settings =
       targets[0].debug->settings()->build_settings();
 
   std::stringstream file;
   file << "# Generated by GN. Do not edit.\n\n";
   file << "{\n";
   file << "  'skip_includes': 1,\n";
+
+  if (targets[0].debug->settings()->IsMac()) {
+    // Global settings for make. This must match common.gypi :(

[Nico, 2013/10/28 23:05:14]

Oh, here it is. Maybe add a comment to that other place saying
"make_global_settings is written elsewhere". I'd also say "for ninja" instead of
or in addition to "for make".

You probably want to write this on other platforms that do clang builds too?

+    file << "  'make_global_settings': [\n";
+    file << "    ['CC', 'third_party/llvm-build/Release+Asserts/bin/clang'],\n";
+    file <<
+        "    ['CXX', 'third_party/llvm-build/Release+Asserts/bin/clang++'],\n";
+    file << "    ['CC.host', '$(CC)'],\n";
+    file << "    ['CXX.host', '$(CXX)'],\n";
+    file << "  ],\n";
+  }
+  // TODO(brettw) android.
+
   file << "  'targets': [\n";
 
   for (size_t i = 0; i < targets.size(); i++) {
     switch (targets[i].debug->output_type()) {
       case Target::COPY_FILES:
       case Target::CUSTOM:
       case Target::GROUP:
         break;  // TODO(brettw)
       case Target::EXECUTABLE:
       case Target::STATIC_LIBRARY:
       case Target::SHARED_LIBRARY:
       case Target::SOURCE_SET: {
         GypBinaryTargetWriter writer(targets[i], file);
         writer.Run();
         break;
       }
       default:
         CHECK(0);
     }
   }
 
   file << "  ],\n}\n";
 
   base::FilePath gyp_file_path = debug_build_settings->GetFullPath(gyp_file);
   std::string contents = file.str();
   file_util::WriteFile(gyp_file_path, contents.c_str(),
                        static_cast<int>(contents.size()));
 }