p4merge does not properly handle the case where "/dev/null" is passed as a filename. Work it around by creating a temporary file for this purpose. Reported-by: Jeremy Morton <admin@game-point.net> Signed-off-by: David Aguilar <davvid@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com> --- Needs to be amended with Tested-by when a report comes...