> * the current install time bundling of setuptools in `ensurepip` is likely to be replaced by `pip` dynamically installing both `setuptools` & `wheel` when asked to build from a source archive when no other build system has been specified. With PEP 517 approved, it's entirely plausible that this will happen as part of the `pip 10.0.0` release. So we *won't* be bundling wheel as part of ensurepip, since doing so would conflict with the plan to unbundle setuptools.

Actually PEP 518 provides the mechanism we need for this, and it's already implemented in pip's master branch (what will become pip 10). I don't remember off the top of my head if that covers 100% of the cases yet, but if it doesn't that's just a SMOP. It's entirely plausible that Python 3.7 ships without setuptools included in ensurepip.