Re: add installation information for the tarball users

[Jose E. Marchesi]

>> > +  + Pre-built package name:
>> > +    - On Debian and Debian-based systems: tcl-dev, tk-dev,
>> > +    - On Red Hat distributions: tcl-devel, tk-devel.
>> > +    - Other: https://repology.org/project/tk/versions
>> 
>> The GUI also has a run-time dependency on tcllib.  It is only required
>> for the handling of JSON data, and it is in the TODO to make the GUI
>> using libjson-c as poke does, but in the meanwhile tcllib is needed.
>
> Yes, on the CentOS 8 machine I noticed that 'tcl-devel' and 'tk-devel'
> are not all that's needed. The build produced and installed an executable
> named 'poke-gui' but when run it complains that some json library is not
> found.
>
> I propose to find out about this during portability testing, tomorrow
> or this week.
>
> The info was not present in etc/hacking.org, therefore my patch is not
> losing information.
>
>> The Debian package with tcllib is `tcllib'.
>
> Good info, thanks.
>
>> Other than that, this is OK for master.
>
> Can I push this now, and update the DEPENDENCIES file once I have found
> out more?

Sure.