systemd/udev/hotplug installation on Ubuntu 19.10

[John Ackermann N8UR]

Just built gpsd from head.  Trying to get the udev hotplug stuff
working, ultimately for multiple receivers, but for now just one would
be nice.

Following the troubleshooting guide, I tried "make udev-install" and no
target was found.  So I did "sudo scons udev-install" which did install
the udev rules in /lib/udev/rules.d

But there was no hotplug action after doing so.  The FAQ mentions
gpsd.hotplug living in /lib/udev, but it hadn't been installed.  I
manually copied it from the source dir to /lib/udev and chmod'd it a+x.

Plugged and unplugged.  Still no hotplug activity in /var/log/syslog.

Per the troubleshooting guide, I cd'd to /lib/udev and ran "sudo
./gpsd-hotplug add /dev/ttyACM0"

Syslog reports:
May  1 10:04:10 lintty gpsd.hotplug: no device

although /dev/ttyACM0 exists.

The hotplug script indicates that it gets its info about the control
socket and options from any of /etc/default/gpsd, /etc/sysconfig/gpsd,
/etc/conf.d/gpsd, but none of those exist.  There doesn't seem to be a
gpsd config file anywhere in /etc.

/lib/systemd/services contains the three gpsd files, but they also refer
to a configuration file in those same non-existent locations in /etc.

I've looked in the tree and don't find anything that is obviously
intended to be the missing config file.

I don't know if it's just the config file that is missing, or if there
are other bits that aren't getting installed, or if there is something
else in the Ubuntu udev/hotplug system that has changed.  Any guidance
on what to do?

And once we get the basics working, what's needed to get multiple
devices working (or will that come automatically once this underlying
problem is resolved)?

Thanks,
John