Merge topic 'configure-log-find-foo-fixes'

3ac505f79d cmFindCommon: log search path variables
e98381af21 cmFindBase: skip writing `names` and `*_directories` when empty

Acked-by: Kitware Robot <kwrobot@kitware.com>
Acked-by: buildbot <buildbot@kitware.com>
Merge-request: !10772