This is needed for Animal Crossing 2.0.0, which has >99000 fucking files.
We now do several passes over dir/file tables instead of one pass,
doing entire hash tables before we touch dir/file tables. Thus we
no longer need to simultaneously allocate hash table and dir/file table space.
In addition, we now do repeated passes building a segment of hash tables
at a time, when insufficient memory is available. Similar is also now the
case for file/dir tables, we try 0x40000 work buffer and divide by 2
until we successfully alloc. We don't allow a work buffer <0x4000, for
write/perf reasons. If a game triggers that, let me know I guess.
Hard to imagine a worse torture-test for this code than animal crossing.
