Is it OK to stabilize =dev-haskell/cereal-0.4.1.0 ? If so, please CC all arches which have stable keywords for older versions of this package.
This version has been removed from the tree. Upstream has a test suite, but it doesn't fail properly at the moment. I've sent a fix. Hopefully they'll integrate it, we can version bump, and then stabilize the new version when there's a test suite to make everyone's life easier.