Hello everyone,

I've experimented with the sample pack/unpack implementation and found
that it does define *null* which happens to be a unique cons (created
using '(null)). One cannot just use '(null) from their own code using
the pack/unpack functionality as that's a different cons, so to make use
of it, it needs to be exported and documented as such. I don't think
it's a good idea to make the specifics implementation-dependent, so I'm
looking for feedback how good of an idea it is to add *null* to the list
of exported identifiers for the (srfi 167 engine) library (as (srfi 167
pack) isn't a thing). Bikeshedding for a different library (like (srfi
167 memory) representing the backend) or name (*null* is an unprefixed
one, so that could be icky) is welcome.

Vasilij