gimp language bug

There is a preference item in gimp that sets the language for the interface
However this does not work at all

This happens in app/language.c, in the aptly named language_init()

through prints, I've been able to determine that setting the language to french
will lead to the gstring "fr" being passed to language_init()


After a few useless lines, it boils down to this:

/* We already set the locale according to the environment, so just
* return early if no language is set in gimprc.
*/
if (! language)
return;

g_setenv ("LANGUAGE", language, TRUE);
setlocale (LC_ALL, "");


According to
https://www.gnu.org/software/gettext/manual/html_node/Locale-Environment-Variables.html

LANGUAGE should supersede LC_ALL for gnu gettext.

which apparently does not happen.

Also note that the value is bogus for us anyway: fr means nothing, we need
fr_FR to set the language to french here.

I have zero idea whether this is an old feature of gettext that got removed
recently, or if we deactivated it for whatever reasons, but here we are:
the gimp language preference feature is broken.