localhost lucas # equery d sdl-image
[ Searching for packages depending on sdl-image... ]
localhost lucas # emerge --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>`.  Packages that are listed in
*** WARNING ***  package.provided (see portage(5)) will be removed by
*** WARNING ***  depclean, even if they are part of the world set.
*** 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 --newuse --deep world` prior to depclean.

Calculating dependencies... done!

Packages installed:   613
Packages in world:    54
Packages in system:   56
Unique package names: 613
Required packages:    613
Number removed:       0
 * GNU info directory index is up-to-date.
localhost lucas #