fully-qualified font names for clients' benefit. Clients only pay for
the font names once they request the FC_FILE property from an
FcPattern, but the font name is malloc'd at that point (i.e. not
mmapped: that's impossible, since it may vary between machines.)
Clients do have to pay for a copy of the path name per cache file.
Note that FcPatternGetString now does some rewriting if you ask for an
FC_FILE, appending the pathname as appropriate.
fonts.cache-1 files (e.g. for grepping and validation of the mmap
codepath), as per James Cloos' request.
Remove done 'TODO' comment.
Updates for development release 2.3.90.