avahi: remove obsolete pkg-config env vars for cross builds.
cryptsetup: remove obsolete settings for cross builds.
glib: remove obsolete settings for cross builds.
kmod: remove obsolete settings for cross builds.
libudev: remove obsolete settings for cross builds.
xbps: remove obsolete settings for cross builds.
Revert "systemd: do not run machine-id-setup nor enable getty@tty1 at post-install."

This reverts commit 0090b549c02f0b710a3a13b500da4578b12dc774.
systemd: revbump for the last commit's revert.