This change fixes some bugs relating to the Makefile and the
systemd watchdog notifier system. We have also removed the run.sh
script which was the culprit of latter problem (not sure exactly
how, but probably something to do with PIDs).
This change adds a "watchdog notifier" utility which tracks the
health of request handlers and notifies an external systemd
watchdog if everything looks good. This allows us to cause a
termination if any request handlers get hung.
Saxon Nelson-Milton