Instead of passing directory information around in separate variables,
collect it all in an FcCache structure. Numerous internal and tool
interfaces changed as a result of this.
Charsets are now pre-frozen before being serialized. This causes them to
share across multiple fonts in the same cache.
Pagesize no longer matters in architecture decisions, the entire cache file
is mmaped into the library. However, lots of intptr_t values are in use now,
so that value is important.
fc-lang now requires fcserialize.c, which has been added to the repository.