Fully qualify path to cl.exe for ninja windows, and support *_wrapper from environment

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 706 matching lines @@
   """Format as an 'environment block' directly suitable for CreateProcess.
   Briefly this is a list of key=value\0, terminated by an additional \0. See
   CreateProcess documentation for more details."""
   block = ''
   nul = '\0'
   for key, value in envvar_dict.iteritems():
     block += key + '=' + value + nul
   block += nul
   return block
 
+def _ExtractCLPath(output_of_where):
+  """Gets the path to cl.exe based on the output of `where`."""
+  # Take the first line, as that's the first found in the PATH.
+  return output_of_where.strip().splitlines()[0].strip()
+
 def GenerateEnvironmentFiles(toplevel_build_dir, generator_flags, open_out):
   """It's not sufficient to have the absolute path to the compiler, linker,
   etc. on Windows, as those tools rely on .dlls being in the PATH. We also
   need to support both x86 and x64 compilers within the same build (to support
   msvs_target_platform hackery). Different architectures require a different
   compiler binary, and different supporting environment variables (INCLUDE,
   LIB, LIBPATH). So, we extract the environment here, wrap all invocations
   of compiler tools (cl, link, lib, rc, midl, etc.) via win_tool.py which
   sets up the environment, and then we do not prefix the compiler with
   an absolute path, instead preferring something like "cl.exe" in the rule
   which will then run whichever the environment setup has put in the path.
   When the following procedure to generate environment files does not
   meet your requirement (e.g. for custom toolchains), you can pass
   "-G ninja_use_custom_environment_files" to the gyp to suppress file
   generation and use custom environment files prepared by yourself."""
   if generator_flags.get('ninja_use_custom_environment_files', 0):
     return
   vs = GetVSVersion(generator_flags)
+  cl_paths = {}
   for arch in ('x86', 'x64'):
+    # Extract environment variables for subprocesses.
     args = vs.SetupScript(arch)
     args.extend(('&&', 'set'))
     popen = subprocess.Popen(
         args, shell=True, stdout=subprocess.PIPE, stderr=subprocess.STDOUT)
     variables, _ = popen.communicate()
     env = _ExtractImportantEnvironment(variables)
     env_block = _FormatAsEnvironmentBlock(env)
     f = open_out(os.path.join(toplevel_build_dir, 'environment.' + arch), 'wb')
     f.write(env_block)
     f.close()
 
+    # Find cl.exe location for this architecture.
+    args = vs.SetupScript(arch)
+    args.extend(('&&', 'where', 'cl.exe'))
+    popen = subprocess.Popen(args, shell=True, stdout=subprocess.PIPE)
+    output, _ = popen.communicate()
+    cl_paths[arch] = _ExtractCLPath(output)
+  return cl_paths
+
 def VerifyMissingSources(sources, build_dir, generator_flags, gyp_to_ninja):
   """Emulate behavior of msvs_error_on_missing_sources present in the msvs
   generator: Check that all regular source files, i.e. not created at run time,
   exist on disk. Missing files cause needless recompilation when building via
   VS, and we want this check to match for people/bots that build using ninja,
   so they're not surprised when the VS build fails."""
   if int(generator_flags.get('msvs_error_on_missing_sources', 0)):
     no_specials = filter(lambda x: '$' not in x, sources)
     relative = [os.path.join(build_dir, gyp_to_ninja(s)) for s in no_specials]
     missing = filter(lambda x: not os.path.exists(x), relative)
     if missing:
       # They'll look like out\Release\..\..\stuff\things.cc, so normalize the
       # path for a slightly less crazy looking output.
       cleaned_up = [os.path.normpath(x) for x in missing]
       raise Exception('Missing input files:\n%s' % '\n'.join(cleaned_up))