Merge branch 'ew/http-walker' into jk/http-walker-limit-redirect

* ew/http-walker:
  list: avoid incompatibility with *BSD sys/queue.h
  http-walker: reduce O(n) ops with doubly-linked list
  http: avoid disconnecting on 404s for loose objects
  http-walker: remove unused parameter from fetch_object

diff --cc http-walker.c
Simple merge

diff --cc http.c
Simple merge