See merge request nexedi/slapos!1693

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.