sempron ~ # emerge -p --depclean
*** WARNING *** Depclean may break link level dependencies. Thus, it is
*** WARNING *** recommended to use a tool such as `revdep-rebuild` (from
*** WARNING *** app-portage/gentoolkit) in order to detect such breakage.
*** WARNING ***
*** WARNING *** Also study the list of packages to be cleaned for any obvious
*** WARNING *** mistakes. Packages that are part of the world set will always
*** WARNING *** be kept. They can be manually added to this set with
*** WARNING *** `emerge --noreplace <atom>`.
*** WARNING ***
*** WARNING *** As a safety measure, depclean will not remove any packages
*** WARNING *** unless *all* required dependencies have been resolved. As a
*** WARNING *** consequence, it is often necessary to run
*** WARNING *** `emerge --update --deep world` prior to depclean.
Calculating dependencies... done!
Dependencies could not be completely resolved due to
the following required packages not being installed:
~kde-base/kde-env-3 required by kde-base/kdelibs-3.5.2-r6
Have you forgotten to run `emerge --update --deep world` prior to depclean?
sempron ~ #