Fix missing variable MSVS expansion of copies arguments with Ninja.

test/ninja/normalize-paths-win/normalize-paths.gyp

 # Copyright (c) 2010 Google Inc. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 {
   'targets': [
     {
       'target_name': 'Some_Target',
       'type': 'executable',
       'msvs_settings': {
@@ skipping 12 matching lines @@
       'msvs_settings': {
         'VCLinkerTool': {
           'OutputFile': '$(OutDir)\\things\\AnotherName.exe',
         },
       },
       'sources': [
         'HeLLo.cc',
       ],
     },
     {
+      'target_name': 'Copy_Target',
+      'type': 'none',
+      'copies': [
+        {
+          'destination': '<(PRODUCT_DIR)',
+          'files': [
+            '$(VSInstallDir)\\bin\\cl.exe',
+          ],
+        },
+      ],
+    },
+    {
       'target_name': 'action',
       'type': 'none',
       'msvs_cygwin_shell': '0',
       'actions': [
         {
           'inputs': [
             '$(IntDir)\\SomeInput',
             '$(OutDir)\\SomeOtherInput',
           ],
           'outputs': [
             '<(PRODUCT_DIR)/ReSuLt',
             '<(SHARED_INTERMEDIATE_DIR)/TempFile',
             '$(OutDir)\SomethingElse',
           ],
           'action_name': 'Test action',
           # Unfortunately, we can't normalize this field because it's
           # free-form. Fortunately, ninja doesn't inspect it at all (only the
           # inputs and outputs) so it's not mandatory.
           'action': [],
         },
       ],
     },
   ],
 }