Update the python version for python-lxml and python-ply packages.
'dblate' now depends on python39, so that will be installed and made the
default by alternatives, so make sure that these python packages are
also available for that python version.
Appveyor has quite restrictive concurrent job limits for free projects,
so reduce the job's runtime by dropping 'make check' to avoid blocking
(since we're now also running that in a GitHub action).
We're bumping up against the 1hr free job duration limit on AppVeyor, so
use 'make -j$(nproc)' to allow things to build slightly faster.
Restructure the way build_script: is written in YAML, so it's slightly less
repetitive and easier to add that.
Also skip 'make check' on x86, since it currently just hangs. :(
Install autoconf and automake, and run winsup/autogen.sh, and don't have
it silently ignore failures.
On AppVeyor:
- use latest VM image, to reduce time spent installing updates.
- run the testsuite, but ignore the result, as some tests don't work
correctly.
- hardcode the python-lxml and python-ply packages to install, so we get
ones for the right python.
- install texlive collections now needed to build documentation.
On github:
- Use a copr for cocom, since RPMSphere's package updates don't track
fedora:latest very efficently.
This is a slightly more polished version of the configuration being used
for CI builds at https://ci.appveyor.com/project/cygwin/cygwin, which is
not currently under version control.
Jon Turney