Help with Qt internationalization

[Peter Eisentraut <peter_e@gmx.net>]

I'm dealing with a bug in the Qt pluging of Licq: #123836

Licq uses the Qt interfaces for message translation.  Apparently, Qt 
ignores the standard locale environment variables.  None of

LC_ALL=fr_FR
LC_ALL=fr
LC_MESSAGES=fr_FR
LC_MESSAGES=fr

succeed to change the language.  But

LANG=fr
LANG=fr_FR

work.  I also notice that none of these environment variables work to 
change the language of a random KDE application like konsole.  Can 
anyone explain how the Qt internationalization facilities work and how 
the user is to set up his environment properly?