[Fontconfig] ISO 15924 font selection

[Patrick Lam]

Gerrit Sangel wrote:
> But I only saw in my config files options to generally define an order of font 
> substition, but not according to language and script tags?

Hi Gerrit,

fontconfig can substitute fonts by two-letter language code. The idea is
to set up a match rule that matches lang="jp" for instance and then to
substitute sans for your Japanese font for that language.

Firefox does use fontconfig when it uses pango (which is the default).

pat