* Always study the list of packages to be cleaned for any obvious
* mistakes. Packages that are part of the world set will always
* be kept. They can be manually added to this set with
* `emerge --noreplace <atom>`. Packages that are listed in
* package.provided (see portage(5)) will be removed by
* depclean, even if they are part of the world set.
*
* As a safety measure, depclean will not remove any packages
* unless *all* required dependencies have been resolved. As a
* consequence of this, it often becomes necessary to run
* `emerge --update --newuse --deep @world` prior to depclean.
Calculating dependencies ..... done!