Merge branch 'jh/memihash-opt'

The name-hash used for detecting paths that are different only in cases (which matter on case insensitive filesystems) has been optimized to take advantage of multi-threading when it makes sense. * jh/memihash-opt: name-hash: add test-lazy-init-name-hash to .gitignore name-hash: add perf test for lazy_init_name_hash name-hash: add test-lazy-init-name-hash name-hash: perf improvement for lazy_init_name_hash hashmap: document memihash_cont, hashmap_disallow_rehash api hashmap: add disallow_rehash setting hashmap: allow memihash computation to be continued name-hash: specify initial size for istate.dir_hash table