cond-expand ice-9 and-let-str, receive

[Kevin Ryde]

Nosing around cond-expand, it occurred to me it might be nice if the
(ice-9 and-let-star) and (ice-9 receive) modules were setup to
cond-expand-provide srfi-2 and srfi-8, the same as the actual srfi
modules do.

If the features (ie. and-let* and receive) are made available then I'd
think they may as well be indicated by cond-expand, without worrying
exactly which module it is that brought them into scope.