setuptools with a GitHub non-release

[Edgar Fuß <ef%math.uni-bonn.de@localhost>]

I'm trying to (locally) package a non-release from a GitHub commit on 
a branch that is after the latest release on that branch and I get 
an error from setuptools:

LookupError: setuptools-scm was unable to detect version for [...]

Make sure you're either building from a fully intact git repository or PyPI tarballs. Most other sources (such as GitHub's tarballs, a git checkout without the .git folder) don't contain the necessary metadata and will not work.

For example, if you're using pip, instead of https://github.com/user/proj/archive/master.zip use git+https://github.com/user/proj.git#egg=proj

How do I handle this?