- Change package to use obs_scm source service. Upstream now longer
publishes xz tarballs.
- Add libtool BuildRquires and call autoreconf in prep: git source
trees are not bootstrapped.

The build fail observed in Factory is unrelated to sile, but is actually
a bug in lua-vstruct. Fix for that has also been submitted as
https://build.opensuse.org/request/show/1176181