gn: fix build with GCC 5

tools/gn/xcode_writer.cc

 // Copyright 2016 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/xcode_writer.h"
 
 #include <iomanip>
 #include <map>
 #include <memory>
 #include <sstream>
@@ skipping 152 matching lines @@
   for (const SourceFile& file : target->sources()) {
     if (base::EndsWith(file.GetName(), kEarlGreyFileNameIdentifier,
                        base::CompareCase::SENSITIVE) ||
         base::EndsWith(file.GetName(), kXCTestFileNameIdentifier,
                        base::CompareCase::SENSITIVE)) {
       xctest_files.push_back(file);
     }
   }
 
   // Call recursively on public and private deps.
-  for (const auto& target : target->public_deps()) {
-    SearchXCTestFiles(target.ptr, xctest_files_per_target);
+  for (const auto& t : target->public_deps()) {
+    SearchXCTestFiles(t.ptr, xctest_files_per_target);
     const Target::FileList& deps_xctest_files =
-        (*xctest_files_per_target)[target.ptr];
+        (*xctest_files_per_target)[t.ptr];
     xctest_files.insert(xctest_files.end(), deps_xctest_files.begin(),
                         deps_xctest_files.end());
   }
 
-  for (const auto& target : target->private_deps()) {
-    SearchXCTestFiles(target.ptr, xctest_files_per_target);
+  for (const auto& t : target->private_deps()) {
+    SearchXCTestFiles(t.ptr, xctest_files_per_target);
     const Target::FileList& deps_xctest_files =
-        (*xctest_files_per_target)[target.ptr];
+        (*xctest_files_per_target)[t.ptr];
     xctest_files.insert(xctest_files.end(), deps_xctest_files.begin(),
                         deps_xctest_files.end());
   }
 
   // Sort xctest_files to remove duplicates.
   std::sort(xctest_files.begin(), xctest_files.end());
   xctest_files.erase(std::unique(xctest_files.begin(), xctest_files.end()),
                      xctest_files.end());
 
   xctest_files_per_target->insert(std::make_pair(target, xctest_files));
@@ skipping 459 matching lines @@
     for (auto* object : pair.second) {
       object->Print(out, 2);
     }
     out << "/* End " << ToString(pair.first) << " section */\n";
   }
 
   out << "\t};\n"
       << "\trootObject = " << project->Reference() << ";\n"
       << "}\n";
 }