[Fontconfig] fontconfig performance

[John Ellson]

I apologize if I'm being naive, but is it really necessary for fontconfig
to open 172 files to resolve "serif" ?

    $ strace fc-match serif 2>&1 | grep open | grep fontconfig | wc -l
    172

Perhaps once after a font change, but every time?  Couldn't the result
of recent lookups be cached?

    $ strace fc-match serif 2>&1 | grep open | grep fontconfig | wc -l
    172

And why are some of those files opened multiple times?
 
    strace fc-match serif 2>&1 | grep open | grep fontconfig | sort -u | 
wc -l
    64



John