GN: Check if targets with precompiled headers use unsupported toolchains.

tools/gn/target.h

 // 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.
 
 #ifndef TOOLS_GN_TARGET_H_
 #define TOOLS_GN_TARGET_H_
 
 #include <set>
 #include <string>
 #include <vector>
@@ skipping 316 matching lines @@
   // Checks precompiled headers from configs and makes sure the resulting
   // values are in config_values_.
   bool ResolvePrecompiledHeaders(Err* err);
 
   // Validates the given thing when a target is resolved.
   bool CheckVisibility(Err* err) const;
   bool CheckTestonly(Err* err) const;
   bool CheckAssertNoDeps(Err* err) const;
   void CheckSourcesGenerated() const;
   void CheckSourceGenerated(const SourceFile& source) const;
+  bool CheckPrecompiledHeaders(Err* err) const;
 
   OutputType output_type_;
   std::string output_name_;
   bool output_prefix_override_;
   SourceDir output_dir_;
   std::string output_extension_;
   bool output_extension_set_;
 
   FileList sources_;
   bool all_headers_public_;
@@ skipping 46 matching lines @@
   // Output files. Empty until the target is resolved.
   std::vector<OutputFile> computed_outputs_;
   OutputFile link_output_file_;
   OutputFile dependency_output_file_;
   std::vector<OutputFile> runtime_outputs_;
 
   DISALLOW_COPY_AND_ASSIGN(Target);
 };
 
 #endif  // TOOLS_GN_TARGET_H_