There's a closed pull request on the void-packages repository

gnubg: fix arm, cleanup template.
https://github.com/void-linux/void-packages/pull/25483

Description:
ARM was failing because it looks for python >=2.1.0. However, it
dosen't know that py3 exists and is very different. Hence, it tries
to use python 3.8 - which dosen't work. Setting CFLAGS and LDFLAGS
so that it uses python2.7 makes the build work.

Furthermore, python-devel in hostmakedepends confused it somewhat,
hence removed (it is not required), and python is required at runtime
(shlibs should pick that up, but it /is/ an explicit dependency
for scripting, and if the python package structure changes then
this is required).

Template cleanups:

- fix xlint warnings.
- move if statements below main variables.
- move the homepage to the new GNU location, gnubg.org is dead.
- move distfiles to working location.