Subject: Python uses a bundled expat

From: Marius Bakke <[email-masked]>
Date: Sat, 06 Oct 2018 16:58:13 +0200

Python 2 and 3 are using a bundled Expat (residing under Modules/).

This has been the cause of security vulnerabilities in the past and
should be changed to use Expat from Guix.