CC does not offer such an option as the GPL does.

It may be preferable to get that under 4.0 or later, so you don't need to contact every contributor again if in some years there is intention to switch to a newer version released by Creative Commons.

The now used /var/run thingy solves all these problems nicely. In fact we may eventually remove the use fallback of using sockets in the GNUPGHOMEDIR.