After updating my system with emerge --sync; emerge -u world, the JPEG library was updated to version 7.0, and oowriter failed to start because it was looking for libjpeg.so.62 (see bug #282569). Running 'revdep-rebuild --library=libjpeg.so.62' successfully rebuilt all apps and libraries except kdebase 3.5 and its dependencies (mostly games, but also kwin4; ironically, OpenOffice itself is also still broken). By "successfully" I mean revdep-rebuild --pretend doesn't report them as needing to be rebuilt any more.
*** This bug has been marked as a duplicate of bug 282569 ***