IUSE line needs 'sdl' added, otherwise this package won't merge
You should write us your actual issue and not a guess based on an error message you got. In this case i expect either elementary or ecore with USE=sdl requested evas with USE=sdl, while that flag for evas was dropped. Since i fixed ecore and elementary, this issue should be gone now. Closing as invalid, since evas does not need USE=sdl