bug#19266: 24.4; Font-related window redrawing delays on OS X

[Kirill Ignatiev]

On some further testing, it seems that commenting out the section of
compact_font_caches that calls compact_font_cache_entry works (the
section surrounded in !defined(HAVE_NTGUI)). There are no more
repeated calls to font_open_entity, and fonts are not closed as
before. I am unable to reproduce the redisplay delay with the two-font
example above.

This presumably stops all cached fonts from being closed at all, ever,
so maybe there should be a more elegant solution. This could (?) be an
issue that mark_face_cache just doesn't mark enough fonts, so unused
fonts get discarded and must be loaded again. Also, this doesn't
explain why garbage-collect doesn't seem to trigger font closing.