In commit da5ac4bb60 (cpack: Add `CPACK_INSTALL_CMAKE_CONFIGURATIONS`
variable, 2019-07-10, v3.16.0-rc1~165^2) we added both the variable
and support for `cpack -C` with multiple configurations. Drop the
variable because the `package` target cannot ensure that all of the
configurations are built. Keep the command-line interface so that
it can be used manually in scripts.
Fixes: #19918
Extend the change from commit 1d00ba9ccf (Find: find_package prefers
variable CMAKE_FIND_USE_REGISTRY, 2018-11-13, v3.16.0-rc1~461^2~1)
to cover the system package registry too.
Fixes: #19890
Other multi-word command line options use hyphens to separate
the words, so the --loglevel option introduced in CMake 3.15 was
inconsistent in this regard. Rename it to --log-level but still support
the original --loglevel name to preserve backward compatibility.
Add notes for the changes from commit 33c7ea513d (CPackDeb: Use
`CPACK_PACKAGE_DESCRIPTION_FILE`, 2019-07-11).
Suggested-by: Alex Turbov <i.zaufi@gmail.com>
Add section headers similar to the 3.15 release notes and move each
individual bullet into an appropriate section. Revise a few bullets.
Drop bullets covering internal interfaces.
