[Fontconfig] any possible trouble by adding lang to the pattern by default

[Akira TAGOH]

Hi,

I'm trying to address the case of the unexpected font selection for
non-English languages when running on English locale. particularly
likely to see with non-rich text, because the pattern doesn't have the
appropriate lang object and what a font fontconfig will pick up really
depends on the order of the configuration files. though the order
issue can be worked around with testing the lang in the rule if the
pattern contains the proper lang object. which doesn't help in that
case.

So I guess what we want to do here may be to set the certain language
to the pattern prior to do something in FcConfigSubstitute() if not
available or still may be good to add it as fallback though. the
candidate can be figured out from the locale and/or the environment
variables. (see the suggestion at
https://bugs.freedesktop.org/show_bug.cgi?id=32853)

Does anyone have any mind to do so? it could be added as the weak
binding to avoid putting more score on it but just to give a hint for
much better selection.

-- 
Akira TAGOH