[PATCH v3 0/4] http cleanups

This is a re-roll of dm/http-cleanup. I've also included a test for chunked http pushes that has been sitting on my side for some time.

Note to Junio: these patches should apply safely on sp/maint-clear-postfields. Actually, the first patch depends on it.

[1/4] t5541-http-push: add test for chunked [2/4] http: make curl callbacks match contracts from curl header [3/4] http-push: use const for strings in signatures [4/4] http-push: refactor curl_easy_setup madness

 http-push.c          |  152 +++++++++++++++++---------------------------------
 http-walker.c        |    4 +-
 http.c               |   12 ++--
 http.h               |    6 +-
 remote-curl.c        |    2 +-
 t/t5541-http-push.sh |   28 +++++++++-
 6 files changed, 90 insertions(+), 114 deletions(-)