Explicitly set BS_NONE for synth 503.

can happen if we gunzip on fetch.

By default IP renders as STRING with just the IP number, so if you
want to get the port number there too, you have to do something
like:

	set resp.http.where = client.ip + ":" + std.port(client.ip);

Not too elegant, but it will do.

Remove the "hard-coded" "foo.port" VCL variables.

healthy, rather than have hardcoded variables for
req.backend and bereq.backend's health.

use it to rename {beresp,resp,obj}.response to *.reason while
still keeping the old ones working.

Use it to also eliminate the already duplicated req.request
and bereq.request (now: *.method)

Initial doc pulled from vcl.rst

Generate doc/sphinx/reference/vcl_var.rst based on this.

log it.  Parallel use of sockets would force us to add locking
and that's simply not worth it.

Also:

Fixes #1376

Removed the comma-separated delimiting of this option parsing, as that
conflicted with comma characters often used in backend names. Use
multiple arguments to have several filters.

Parser honors backslash escapes. This makes it possible to list names
containing '.' (also common with backend names).

Fixes: #957

With proper flushing happening on idle, this option is obsolete.

the exact same byte sequence from the backend, Gzip, Gunzip or ESI
expansion.

(See also: #940)

Inspired by:  An old patch from Mithrandir I found in my mailbox

parts of config.h we don't need anymore

Detectived by:	scn

Fixes:	#1359