Port JGit's HistogramDiff algorithm over to C. Rough numbers (TODO) show
that it is faster than its --patience cousin, as well as the default
Meyers algorithm.
The implementation has been reworked to use structs and pointers,
instead of bitmasks, thus doing away with JGit's 2^28 line limit.
We also use xdiff's default hash table implementation (xdl_hash_bits()
with XDL_HASHLONG()) for convenience.
Signed-off-by: Tay Ray Chuan <rctay89@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Johannes Sixt