[mythtv] Why are themes downloaded to /etc/mythtv?

[Raymond Wagner]

After a bit of a discussion with Mike Dean in IRC, we've decided that 
the real problem is that MythTV should not be storing configuration data 
and cache data in the same location.  To that end, we've come up with a 
potential solution

1. Get rid of mysql.txt.  This one has been a long time coming ever 
since config.xml showed up with the UPnP server and detection.  This 
means some of the options mysql.txt used to offer will need to be 
migrated to config.xml, and a chunk of the database selection code will 
need to be rewritten.

2. Move the name and location of config.xml to disconnect it from the 
cache directory.  Use something like mythtv.xml or mythtv-config.xml.  
Have a default location of $HOME/.mythtv.xml, with a fall through to 
SYSCONFDIR/mythtv.xml, where SYSCONFDIR is compiled in statically with 
the standard --sysconfdir flag.  Make the default to that /etc/mythtv/.  
Make this selection very well spelled out in the logs with the default 
logging parameters.

3. Keep the rest of the data in its current location of $HOME/.mythtv, 
with an optional override of $MYTHCACHEDIR (as opposed to the old 
$MYTHCONFDIR).  This still contains all the theme and download cache, 
and other temporary files, but since it is divested of configuration 
data, it should be less of an issue for packagers and users to put 
wherever they want and still continue to follow their distro's 
convention.  If packagers want this data shared between multiple users, 
set $MYTHCACHEDIR to its location, and make sure all users are group 
owners with group write permissions.  This could be performed by a 
wrapper script (like Mythbuntu), or by putting the definition into the 
system profile.

Note that MythTV is capable of calling external applications and 
utilities that may well want to store their own data in $HOME.  Running 
any MythTV application with an altered or non-existent home folder 
should be considered very dangerous, and not done.  This does mean I'll 
have to alter the Gentoo ebuilds to comply with this.