When Prestwood is started as either a systemd service or a child
process of Canterbury, this is what it will get.

Signed-off-by: Simon McVittie <smcv@collabora.com>
Reviewed-by: Emanuele Aina <emanuele.aina@collabora.co.uk>
Differential Revision: https://phabricator.apertis.org/D6222