D20059: Take clang-cl into account.

[Aleix Pol Gonzalez]

apol added a reviewer: Windows.

REPOSITORY
  R240 Extra CMake Modules

REVISION DETAIL
  https://phabricator.kde.org/D20059

To: cmollekopf, #windows
Cc: kde-frameworks-devel, kde-buildsystem, michaelh, ngraham, bruns