[Distutils] PEP 517 again

[Donald Stufft]

> On Sep 1, 2017, at 12:23 AM, Nick Coghlan <ncoghlan at gmail.com> wrote:
> 
> 1. Wheel download cache (if this gets a hit, don't even check the package repo)
> 2. Check the package repo for a wheel file (and if you find one, add
> it to the download cache)
> 3. Local build cache (make this interpreter implementation specific)
> 4. Build a local wheel that's specific to the running interpreter implementation

This is basically what exists now. We just force a compatibility tag to handle (4).