fold in 'markerlib' as a new top-level package 'envmarkers'
I will do this, but I want to track it here.
pkg_resources conditionally imports markerlib to enumerate dependencies for .dist-info style distributions. It would be better if this always works without the side effects you might get from importing setuptools. 'envmarkers' is an ugly name that is less likely to have collisions than 'markers'. I might decide to prefix it with an underscore _envmarkers for good measure.