CMAKE_LANG_PLATFORM_ID
CMAKE_<LANG>_PLATFORM_ID
An internal variable subject to change.
This is used in determining the platform and is subject to change.
© 2000–2016 Kitware, Inc.
© 2000–2011 Insight Software Consortium
Licensed under the BSD 3-clause License.
https://cmake.org/cmake/help/v3.5/variable/CMAKE_LANG_PLATFORM_ID.html