Enhance install messages with an "updating" status
During installation CMake will produce output including messages
-- Installing: file1.txt
-- Up-to-date: file2.txt
This does not allow to determine wether file2.txt
was missing prior to installation or if it has been updated.
It would therefore be useful to change the message to
-- Updating: file1.txt
if the file already existed on disk and had to be updated.