[PATCH 1/2] configure: add check for python interepreter name

[David Bremner]

David Bremner <david at tethera.net> writes:

> Currently we hardcode "python" in several places. This makes things
> hard for people who have only commands called python3 and/or
> python2. We also add the name to sh.config to eventually replace the
> current workaround in the test suite.

Pushed, with Tomi's suggested addition of at least removing the hard
coding of python in the configure script itself.