This is a PoC to compile wendelin and slapos-master with python3, and
  specially to run the tests.

Following advice from https://luajit.org/download.html use recent commit id,
but rely on github archive.

Drop obsoleted patch, enforce --with-shared-termcap-library

Also use directly archive with patches.

Changes:
 * use xz archive
 * stabilize patch name
 * update patch to current version

Expose pkgconfig configuration so that other parts can easily fetch it.

See https://bugs-devel.debian.org/cgi-bin/bugreport.cgi?bug=1077190

Drop fmhttp, as it's not needed to make http calls from our deployments, and
the updated version requires much more dependencies for this feature.

The fix for https://github.com/apache/trafficserver/issues/11784 is ready
for 9 branch in https://github.com/apache/trafficserver/pull/11835 , so use
the patch directly until new version is released.

We prefer to change the egg version at a different time (usually inside
a MR containing other changes).