Dear guix maintainers,

Please find attached a patch to add a package for the cachefilesd
daemon, mostly used for read caching of NFS data. I've put in into
linux.scm as it's tightly coupled to the fscache linux module and is
being developed on git.kernel.org.

There's a lint warning for Software Heritage; however i've followed the
convention of using snapshot tarballs from kernel.org (we could also
directly go through git, but this seems less common).

A service will follow as soon as I understand how to correctly write
one.

Kind regards,
Jean-Baptiste