[Fontconfig] robustness of the mmap cache branch

[Patrick Lam]

Matthias Clasen wrote:
> I wonder if it would be a good idea to do a development release or
> at least create a snapshot tarball off the 2-4 branch, to get some wider
> testing, or are there currently any outstanding issues with the mmap
> cache that make a test release impractical ?

I think this is a good idea.  I'm kind of busy until Saturday, but on
Saturday I'll create at least a snapshot tarball.

pat