Avoid MSB8012 in GYP

pylib/gyp/input.py

 # Copyright (c) 2012 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.
 
 from compiler.ast import Const
 from compiler.ast import Dict
 from compiler.ast import Discard
 from compiler.ast import List
 from compiler.ast import Module
 from compiler.ast import Node
@@ skipping 64 matching lines @@
   'product_dir',
   'product_extension',
   'product_name',
   'product_prefix',
   'rules',
   'run_as',
   'sources',
   'standalone_static_library',
   'suppress_wildcard',
   'target_name',
+  'target_extension',
   'toolset',
   'toolsets',
   'type',
   'variants',
 
   # Sections that can be found inside targets or configurations, but that
   # should not be propagated from targets into their configurations.
   'variables',
 ]
 non_configuration_keys = []
@@ skipping 2609 matching lines @@
     ValidateRunAsInTarget(target, target_dict, build_file)
     ValidateActionsInTarget(target, target_dict, build_file)
 
   # Generators might not expect ints.  Turn them into strs.
   TurnIntIntoStrInDict(data)
 
   # TODO(mark): Return |data| for now because the generator needs a list of
   # build files that came in.  In the future, maybe it should just accept
   # a list, and not the whole data dict.
   return [flat_list, targets, data]