Gentoo users that do regular updates, probably already ran into this issue before: Gentoo has pushed libexpat-2 to stable, effectively breaking all applications that depend upon it because of a missing library. While this is quite normal behaviour (the two versions of libexpat are not entirely compatible), it is mostly a very annoying thing, as it is not easy to find out which packages depend on it. Lucky, the Gentoo Forums provided me with a good solution.

Normally, in such a scenario, one would use revdep-rebuild to solve these issues, but, as seen on the forums, it more than occassionally   ...