Read the configuration to get trailer information, and then process
it and store it in a doubly linked list.
The config information is stored in the list whose first item is
pointed to by:
static struct trailer_item *first_conf_item;
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>