Merge topic 'handle_multiple_source_dirs'

b2bc3364f0 CMake: `-S` paths preferred over other provided paths
2e1b7e5b9a Add tests that showcase cmake -S limitations

Acked-by: Kitware Robot <kwrobot@kitware.com>
Acked-by: buildbot <buildbot@kitware.com>
Merge-request: !6874