Further, I don't have libsystemd0 installed on my system at
all, although there are some config files hanging around in /etc.

dpkg -l libsystemd0
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend

|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name                 Version         Architecture    Description
+++-====================-===============-===============-=============================================
rc  libsystemd0:amd64    215-17+deb8u4   amd64           systemd utility library

--
Joel Roth