how to specify which NLS catalogues (po files) to install

["ネルソンヘンリー" <nbsd4ever%gmail.com@localhost>]

I'd like to build and install only the "ja" locale for any package.
The only thing I see
in mk.conf is MKNLS, but that controls whether or not to compile and
install all of
the locale zone files, not limit them to specific ones.

I suppose I could set the environment variable LINGUAS, but not only would I be
very likely to forget just when I really want NLS, but it could be
very tedious doing
it for many packages.  Also, how would I set it for root when just prompted for
root's password to install?

Is there some way, some file, to pass environment variables to the pkgsrc system
as a whole, so that they would be applied to every build and install?

-- 
hnelson