env python - port select or reinplace

[db]

On 28 Apr 2017, at 03:19, Ryan Schmidt <ryandesign at macports.org> wrote:
> Use the latest stable version of python. Or offer variants so the user can choose, and default to the latest stable version.

Could you please take a look at #54054? The port rewrites some paths before copying the files in place — nothing fancy. But maybe there's a more succinct way to do it.