clang/gn/win: Stop running the compiler through `ninja -t msvc -e environment.foo`

build/toolchain/win/setup_toolchain.py

 # Copyright (c) 2013 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.
 #
 # Copies the given "win tool" (which the toolchain uses to wrap compiler
 # invocations) and the environment blocks for the 32-bit and 64-bit builds on
 # Windows to the build directory.
 #
 # The arguments are the visual studio install location and the location of the
 # win tool. The script assumes that the root build directory is the current dir
@@ skipping 137 matching lines @@
 
   # Add header and write it out to the current directory (which should be the
   # root build dir).
   with open("gyp-win-tool", 'w') as tool_file:
     tool_file.write(''.join([tool_source[0],
                              '# Generated by setup_toolchain.py do not edit.\n']
                             + tool_source[1:]))
 
 
 def main():
-  if len(sys.argv) != 6:
+  if len(sys.argv) != 7:
     print('Usage setup_toolchain.py '
           '<visual studio path> <win tool path> <win sdk path> '
-          '<runtime dirs> <target_cpu>')
+          '<runtime dirs> <target_cpu> <include prefix>')
     sys.exit(2)
   tool_source = sys.argv[2]
   win_sdk_path = sys.argv[3]
   runtime_dirs = sys.argv[4]
   target_cpu = sys.argv[5]
+  include_prefix = sys.argv[6]
 
   _CopyTool(tool_source)
 
   cpus = ('x86', 'x64')
   assert target_cpu in cpus
   vc_bin_dir = ''
+  include = ''
 
   # TODO(scottmg|goma): Do we need an equivalent of
   # ninja_use_custom_environment_files?
 
   for cpu in cpus:
     # Extract environment variables for subprocesses.
     env = _LoadToolchainEnv(cpu, win_sdk_path)
     env['PATH'] = runtime_dirs + os.pathsep + env['PATH']
 
     if cpu == target_cpu:
       for path in env['PATH'].split(os.pathsep):
         if os.path.exists(os.path.join(path, 'cl.exe')):
           vc_bin_dir = os.path.realpath(path)
           break
+      include = ' '.join([include_prefix + p
+                          for p in env['INCLUDE'].split(';')])
 
     env_block = _FormatAsEnvironmentBlock(env)
     with open('environment.' + cpu, 'wb') as f:
       f.write(env_block)
 
     # Create a store app version of the environment.
     if 'LIB' in env:
       env['LIB']     = env['LIB']    .replace(r'\VC\LIB', r'\VC\LIB\STORE')
     if 'LIBPATH' in env:
       env['LIBPATH'] = env['LIBPATH'].replace(r'\VC\LIB', r'\VC\LIB\STORE')
     env_block = _FormatAsEnvironmentBlock(env)
     with open('environment.winrt_' + cpu, 'wb') as f:
-        f.write(env_block)
+      f.write(env_block)
 
   assert vc_bin_dir
+  assert '"' not in vc_bin_dir
   print 'vc_bin_dir = "%s"' % vc_bin_dir
-
+  assert include
+  assert '"' not in include
+  print 'include_flags = "%s"' % include
 
 if __name__ == '__main__':
   main()