[CMake] How to report deprecated functionalities (subdirs, install_files...)

[Mathieu Malaterre]

Hi there,

  I would like cmake to report any deprecated functionalities still
being in use on my project (it would ideally return the filename +
line number where it is being used). I was not able to find a way of
doing that. Typically I would like to get rid of call to
install_files() and subdirs() within an in-house project.

Thanks,
-- 
Mathieu