[mythtv-users] Fix for broken lirc package in Ubuntu 20.04

[Stephen Worthington]

As it was in Ubuntu 18.04, so it is in 20.04 - the lirc package is
still broken.  The underlying lirc code is working, so you can
manually configure it if you know how to do that.  But even there, the
Python parts of lirc are now a little out of date and are producing
deprecation warnings.  They are still working for now, but as Python
gets upgraded they will eventually stop working unless fixes are done.
In the mean time, the deprecation warning messages can safely be
ignored.  And only the core configuration code actually works - for
example, the Info button will pop up a link to the wrong place for the
info files.

I have updated my fix script for 18.04 to work with 20.04.  It is on
my web server here:

http://www.jsw.gen.nz/mythtv/lirc-ubuntu-20.04-install.sh

The script for fixing the lirc package in 18.04 is here, should anyone
still need it:

http://www.jsw.gen.nz/mythtv/lirc-ubuntu-18.04-install.sh

The script will download the source package for lirc and compile it in
order to create the missing *.so file - so it will take a while and
create a lot of screen output doing that.  It cleans up all of that
when it finishes.  Once it has been run, you should be able to run
lirc-setup (using sudo) and configure lirc.

I think it may be possible that if you upgrade an existing working
18.04 lirc configuration, it will still work in 20.04.  But I have not
tried that.  And if you needed to reconfigure lirc at some point, the
Python tools would not work.  So I think it is best to run my script
after upgrading.  Please note that my script stops and disables all
the lirc systemd services except for those needed for running lircd,
as they can do various bad things if they are running with the (bad)
default configurations.  If you are using any of the other services
(irexec.service, lircd-uinput.service or lircmd.service) and have
given them valid configurations, then you will need to re-enable and
restart them after the script finishes:

sudo systemctl enable <service name>
sudo systemctl start <service name>

As yet I do not have a real 20.04 system running, as I am waiting for
20.04.1 so that I can do the LTS upgrade from 18.04.  I created my
updated script using a fresh install of Xubuntu 20.04 in a VirtualBox
VM.  One volunteer has tested it for me on a real 20.04 with IR
hardware attached - I would like to thank John Burroughs for helping
do that.  But it is still possible that there may be undiscovered
problems with the script.  So if you have problems, please let me
know.