[Distutils] The future of env markers (was Re: platform_python_implementation not implemented.)

[Vincent Povirk]

> I'm not sure what to do here; going back to defining it as a "subset of
> Python" seems like a backward step, but I'm struggling to see what benefit
> we'd get from the effort of more rigorously defining the grammar.

It'd mean that software not written in Python could more easily work with them.