GN: Fix single-file compilations in VS2017 projects

tools/gn/visual_studio_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/visual_studio_writer.h"
 
 #include <algorithm>
 #include <iterator>
 #include <map>
 #include <memory>
@@ skipping 417 matching lines @@
   }
 
   {
     std::unique_ptr<XmlElementWriter> globals =
         project.SubElement("PropertyGroup", XmlAttributes("Label", "Globals"));
     globals->SubElement("ProjectGuid")->Text(solution_project.guid);
     globals->SubElement("Keyword")->Text("Win32Proj");
     globals->SubElement("RootNamespace")->Text(target->label().name());
     globals->SubElement("IgnoreWarnCompileDuplicatedFilename")->Text("true");
     globals->SubElement("PreferredToolArchitecture")->Text("x64");
+    globals->SubElement("WindowsTargetPlatformVersion")
+        ->Text(kWindowsKitsIncludeVersion);
   }
 
   project.SubElement(
       "Import", XmlAttributes("Project",
                               "$(VCTargetsPath)\\Microsoft.Cpp.Default.props"));
 
   {
     std::unique_ptr<XmlElementWriter> configuration = project.SubElement(
         "PropertyGroup", XmlAttributes("Label", "Configuration"));
     configuration->SubElement("CharacterSet")->Text("Unicode");
@@ skipping 419 matching lines @@
   }
 }
 
 std::string VisualStudioWriter::GetNinjaTarget(const Target* target) {
   std::ostringstream ninja_target_out;
   DCHECK(!target->dependency_output_file().value().empty());
   ninja_path_output_.WriteFile(ninja_target_out,
                                target->dependency_output_file());
   return ninja_target_out.str();
 }