If the filename matches, no other matching is necessary. Fontconfig
doesn't have a fast path for that, so implement one here.
Fontconfig is unlikely to add that fast path, see here:
https://gitlab.freedesktop.org/fontconfig/fontconfig/issues/103
With -O1 builds of Qt and KDE stack, 358 fonts installed according
to KDE systemsetting, on a Ryzen 1800X, startup time of kwrite
decreases as following according to perf stat:
msec task-clock: ~480 ms to ~455 ms
cycles: ~1.73e9 to ~1.65e9
Change-Id: I630a80e4bed2647d5bbd95247005aab7d0cb0363
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@qt.io>
eea99e1e8f