Indeed, the lib/plat- directories should continue to work just fine using linux3, correct?  Or using linux, if we change sys.platform.

(Note: just because we don't import them in the test suite doesn't mean that user code in the field isn't using them...I got a few (trivial it is true, but...) hits from google code search on DLFCN.)

Changing sys.platform as Martin suggests seems like the least painful solution to me.

Note, however, that we have skips in the tests suite that do care about, for example, the FreeBSD OS major version.  FreeBSD does sometimes fix the bugs we've discovered...but as someone else pointed out, this doesn't necessarily happen at a major release boundary, we just use that in the test skipping because it is the easiest thing for us to do.  If sys.platform no longer included the OS major version, the test skips would probably end up being made more accurate.