message: Undefine __cpp_inline_variables on Windows build.
  * MSVC 2017 apparently fails to build abseil-cpp/absl/types/compare.h
  if __cpp_inline_variables is defined.
  * Some MSVC 2017 environment works well w/o this option.
  * Some MSVC 2017 environment still doesn't work even with this option.
diff: '/Zc:strictStrings',
  '/utf-8',
  '/std:c++17',
  + # MSVC 2017 apparently fails to build abseil-cpp/absl/types/compare.h
  + # if __cpp_inline_variables is defined.
  + '/U __cpp_inline_variables', # Undefine the variable
  ],
  },
  'VCLinkerTool': {
  