I'm still eager to accept this work, but because it's based on the setuptools-scm commit, it won't be acceptable until that commit can be accepted, and I'm not at all comfortable releasing that, as it adds a setup_requires requirement to setuptools, which would likely break installation on systems that don't have network connectivity and probably other edge cases. I'll see if I can pull in these changes and rebase them without the setuptools-scm head.
$hgrebase-s7b3adabc2b2f-df2894a03299--keeprebasing4297:7b3adabc2b2f"Switch back to SyntaxError for invalid markers, stops consumers having to import packaging themselves"rebasing4298:6761aee34b69"Update to packaging 16.1"rebasing4299:0fabf2bcc620"Correct tests after the move to packaging 16.1."rebasing4300:4739d78a5064"Merge from master, resolving conflicts."(tippr-164)mergingsetup.pymergingsetuptools/__init__.py
And I've pushed those rebased commits in the pr-164 bookmark.
Unfortunately, it seems the tests for Python 3 aren't passing. They show the same error I get on my system under Python 3 (though at a slightly different stage).