These were added and used by commit 5299141320 (CPackDeb: Enable the DEB
generator on Windows, 2017-06-17, v3.10.0-rc1~445^2) but have not been
used since commit df556e65f2 (cmCPackDebGenerator: Use libarchive to
create .deb file, 2017-08-24, v3.10.0-rc1~220^2).
Provide a standardized way to handle the C++ "standard" headers
customized to be used with current CMake C++ standard constraints.
Offer under directory `cm` headers which can be used as direct
replacements of the standard ones. For example:
#include <cm/string_view>
can be used safely for CMake development in place of the `<string_view>`
standard header.
Fixes: #19491
While some features require external Unix tools the
generator is mostly portable.
By enabling it on Windows it can be used for cross platform
packaging.