libbb: shrink linked list ops (by xmaks AT email.cz)

function                                             old     new   delta
llist_pop                                             33      29      -4
llist_unlink                                          47      28     -19
llist_add_to_end                                      50      31     -19
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 0/3 up/down: 0/-42)             Total: -42 bytes

1 file changed