It was broken by X-Forwarded-For related changes in f7fe817c92a2 (1.3.14)
as hh->offset is no longer 0 for Cookie.

Due to peer->checked always set since rev. c90801720a0c (1.3.0)
by round-robin and least_conn balancers (ip_hash not affected),
the code in ngx_http_upstream_free_round_robin_peer() function
incorrectly reset peer->fails too often.

Reported by Dmitry Popov,
http://mailman.nginx.org/pipermail/nginx-devel/2013-May/003720.html

The $proxy_internal_body_length value might change during request lifetime,
notably if proxy_set_body used, and use of a cached value might result in
incorrect upstream requests.

Patch by Lanshun Zhou.

If nginx was compiled without --with-http_ssl_module, but with some
other module which uses OpenSSL (e.g. --with-mail_ssl_module), insufficient
preprocessor check resulted in build failure.  The problem was introduced
by e0a3714a36f8 (1.3.14).

Reported by Roman Arutyunyan.

This is to avoid setting the TCP_NODELAY flag on SPDY socket in
ngx_http_upstream_send_response().  The latter works per request,
but in SPDY case it might affect other streams in connection.

As of 1.3.9, chunked request body may be available with
r->headers_in.content_length_n <= 0.  Additionally, request body
may be in multiple buffers even if r->request_body_in_single_buf
was requested.

Dependancy tracking introduced in r5169 were not handled absolute path
names properly.  Absolute names might appear in CORE_DEPS if --with-openssl
or --with-pcre configure arguments are used to build OpenSSL/PCRE
libraries.

Additionally, revert part of r5169 to set NGX_INCS from Makefile
variables.  Makefile variables have $ngx_include_opt in them, which
might result in wrong include paths being used.  As a side effect,
this also restores build with --with-http_perl_module and --without-http
at the same time.

Before 1.3.9 an attempt to read body in a subrequest only caused problems
if body wasn't already read or discarded in a main request.  Starting with
1.3.9 it might also cause problems if body was discarded by a main request
before subrequest start.

Fix is to just ignore attempts to read request body in a subrequest, which
looks like right thing to do anyway.