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