Some of the pseudo-merge test helpers (which will be introduced in the
following commit) will want to indicate the total number of commits in
or objects reachable from a pseudo-merge.
Implement a popcount() function that operates on EWAH bitmaps to quickly
determine how many bits are set in each of the respective bitmaps.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
0481cbf912