[Fontconfig] commit: drastic fontconfig speedups

[Patrick Lam]

Hi all,

The folks at SuSE have been profiling and contributing a number of
performance patches for fontconfig, which I've all reviewed and
committed.  The most recent one is for FcFontSetMatch, which they report
gives a 3.5x speedup in fontconfig; that patch rewrote the algorithm by
inlining FcCompare and swapping the order of the loops, blocking fonts
that were ineligible for being the best font.  So while both the old
algorithm and the new algorithm are linear in the number of installed
fonts, the new algorithm is much faster than the old algorithm by doing
a lot less value list compares.

Lots of thanks to Dirk Mueller, Stephen Kulow and Michael Matz!

pat