Bug#936554: freedoom: Python2 removal in sid/bullseye

[mikeonthecomputer at gmail.com]

Upstream Freedoom maintainer here.

We have dropped support for Python 2 entirely in the VCS HEAD (by means
of replacing all shebangs from invoking "python" to "python3"), but
0.11.3 should also be completely compatible with Python 3.  Possible
workarounds for the Debian package might either be to use a python
venv, run an "alias python=python3" before building, or patch all the
invocation lines for python3.

A similar issue arises too with the use of AsciiDoc, whose reference
implementation only has official releases that have a hard depend on
python2.  I think I will add an ASCIIDOC variable to the Makefiles to
control the implementation used, so it could be switched to asciidoctor
for example; this should be a trivial patch to backport.

Unfortunately there is no plan to make a 0.11.4 release, but we are
trying to get a 0.12.0 as soon as we can :)