GN Mac build work

tools/gn/gyp_target_writer.cc

Index: tools/gn/gyp_target_writer.cc
diff --git a/tools/gn/gyp_target_writer.cc b/tools/gn/gyp_target_writer.cc
index 5f350545dcfef13a0156cbdf08c44caec94dfe85..18063e8c032740621e57659f49030896e0e44aaf 100644
--- a/tools/gn/gyp_target_writer.cc
+++ b/tools/gn/gyp_target_writer.cc
@@ -37,6 +37,19 @@ void GypTargetWriter::WriteFile(const SourceFile& gyp_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++) {