Let GYP recognize the 'WDK_DIR' environment variable when generating ninja output on Windows.

pylib/gyp/msvs_emulation.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.
 
 """
 This module helps emulate Visual Studio 2008 behavior on top of other
 build systems, primarily ninja.
 """
 
 import os
@@ skipping 116 matching lines @@
 class MsvsSettings(object):
   """A class that understands the gyp 'msvs_...' values (especially the
   msvs_settings field). They largely correpond to the VS2008 IDE DOM. This
   class helps map those settings to command line options."""
 
   def __init__(self, spec, generator_flags):
     self.spec = spec
     self.vs_version = GetVSVersion(generator_flags)
     self.dxsdk_dir = _FindDirectXInstallation()
 
+    # Try to find an installation location for the Windows DDK by checking
+    # the WDK_DIR environment variable, may be None.
+    self.wdk_dir = os.environ.get('WDK_DIR')
+
     supported_fields = [
         ('msvs_configuration_attributes', dict),
         ('msvs_settings', dict),
         ('msvs_system_include_dirs', list),
         ('msvs_disabled_warnings', list),
         ]
     configs = spec['configurations']
     for field, default in supported_fields:
       setattr(self, field, {})
       for configname, config in configs.iteritems():
@@ skipping 12 matching lines @@
         '$(InputPath)': '${source}',
         '$(InputName)': '${root}',
         '$(ProjectName)': self.spec['target_name'],
         '$(PlatformName)': 'Win32', # TODO(scottmg): Support for x64 toolchain.
     }
     # Chromium uses DXSDK_DIR in include/lib paths, but it may or may not be
     # set. This happens when the SDK is sync'd via src-internal, rather than
     # by typical end-user installation of the SDK. If it's not set, we don't
     # want to leave the unexpanded variable in the path, so simply strip it.
     replacements['$(DXSDK_DIR)'] = self.dxsdk_dir if self.dxsdk_dir else ''
+    replacements['$(WDK_DIR)'] = self.wdk_dir if self.wdk_dir else ''
     return replacements
 
   def ConvertVSMacros(self, s, base_to_build=None):
     """Convert from VS macro names to something equivalent."""
     env = self.GetVSMacroEnv(base_to_build)
     return ExpandMacros(s, env)
 
   def AdjustLibraries(self, libraries):
     """Strip -l from library if it's specified with that."""
     return [lib[2:] if lib.startswith('-l') else lib for lib in libraries]
@@ skipping 284 matching lines @@
   return vs.SetupScript()
 
 def ExpandMacros(string, expansions):
   """Expand $(Variable) per expansions dict. See MsvsSettings.GetVSMacroEnv
   for the canonical way to retrieve a suitable dict."""
   if '$' in string:
     for old, new in expansions.iteritems():
       assert '$(' not in new, new
       string = string.replace(old, new)
   return string