I have the following patch in pkg_rolling-replace. It's obviously not the right thing, but it has worked well enough to allow pkg_rr to replace both py24-foo and py25-foo. The right thing, I think, would be for the binary package (and the pkg db entry for an installed package) to have a list of variables that must be set at build time to create the package, and for "make replace" to pay attention to that. I think your patch is an incremental improvement and am in favor of checking it in. There is of course a lot more to do, but that will help a lot of people.
Attachment:
pgpV74Su3M6Oo.pgp
Description: PGP signature