logind: add MESSAGE_IDs to interesting events
build-sys: install two more man aliases
man: add Arch Linux entry to systemd-nspawn(5)

Archlinux has a similar tool to debbotstrap in the arch-install-scripts
package that will install to a specified directory. This is generally
used for installation, so the -d flag must be passed to tell it to
install to a non-mountpoint directory.