steps to reproduce : install nwn, nwmovies . do not install nwmouse => nwn won't start ldd /opt/nwn/nwmovies.so libelf.so.1 => not found and dev-libs/libelf does not provide libelf.so.1 (however nwn works with both nwmovies and nwmouse because nwmouse is compiled and linked against installed libelf)
Created attachment 143849 [details] emerge --info output
It's now fixed. I have moved the local libelf to games-rpg/nwn and updated all deps. Thanks for reporting this. Denis.