the previous code would round 9007199254740991 to 9007199254740992

Tested on linux and the four vtest SunOS variants

vtest would segfault due to a null pointer access on empty
headers

Closes #2905

we missed to change these when we changed the VCL_INT typedef from long
to int64_t

Should we add VCL_INT_MAX / VCL_INT_MIN (and for the other integer
types, respectively)?

Ref: doc/README.WRITING_RST.rst

in particular:

- remove defintion lists (Description/Example)
- examples as code blocks::
- argument names as *emphasis*
- ``literals``

Ref: doc/README.WRITING_RST.rst

Spotted by @lkarsten

This commit attempts to make it easier to read build output, and
hopefully makes configure.ac easier as well.

-Wall has already been added around line 645, no need to add it twice.

On GCC -Wreturn-type is a part of -Wall, which we enable elsewhere.

    https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html

On Clang -Wreturn-type is enabled by default:

    https://clang.llvm.org/docs/DiagnosticsReference.html#wreturn-type

Same with -Wswitch as -Wreturn-type, so that can be removed as well.

Finally, use spaces instead of tabs to make cc output shorter and more
readable.

I did consider generalizing VCL_IterDirector which handles backend
iterations for the CLI, but found the complications not worth the
savings for such a trivial function.

Thank you, @Dridi

- yes, allocations outside the lock were motivated by minimizing the
  critical section, but n_backend could actually change, so this was
  wrong. As we use an RW lock, doing more work under it should only have
  marginal impact.

- n_backend == 0 is probably best handled as a special case

With that, (almost) only libvgz carries goto statements from zlib.

This isn't changing any of the previous semantics, in particular the
AN(be) assertion from the "ok:" jump is honored by all code paths
formerly leading to it.

Previously, the bitmap was allocated on the stack prior to the magic
check of shardd, which is now fixed at the expense of a potential code
style violation. But more importantly, we currently read the number of
backends prior to acquiring the read lock, but there is no evidence
that this was done on purpose and not overlooked, besides moving a
possibly expensive state initialization outside of the critical
section.

If that was on purpose, please document it.

References #2912

things I seem to only notice in my email reader...

Previously, we did not test for the storage being actually freed and
freeing only happened for passes, either explicit or a hit on hfm or
hfp, but not the for the object becoming the hfm/hfp.

We now handle incremental freeing for hfm/hfp as for private objects and
add a test which actually checks that storage is being freed on the go.

Fixes #2653

also polished http_swallow_body() and made the body dump prefix name
more consistent to indicate the receive method:

	(new)		(old)

	chunked		body
	c-l		body
	eof		rxeof

per-VCL, so cleanup should only happen on the last discard event.

This brought confusion to #2576, and while that ticket is probably
easier to debug if the counters were per-vcl, I think it is important
to keep the "per-vmod" behaviour around as an example.

the child process.

Inspired by: #2471

mutex, for instance the VFP might have nipped out for more storage.

Fixes: #2572

On the client side, we impose a total timeout, yet on the client side we
use between_bytes_timeout and do not care about the total (<- we might
want to reconsider this).

Yet HTC_RxStuff only implemented a total timeout, for which we
effectively used first_byte_timeout + between_bytes_timeout. Yet if
first_byte_timeout was not used up, the effective timeout between bytes
could be substantially longer than between_bytes_timeout (initially
analyzed by @daghf).

We now add a duration argument td to HTC_RxStuff which will be used in
addition to (or instead of) the existing total timeout tn. Either td or
tn must be given.

Testcase originally by @fgsch, slightly modified to avoid an assertion
failure in vtc_server due to the connection being closed by varnish.

Fixes #2395

Fixes #2914

Ref: a0436a43

Lines starting with a space are interpreted as a "block quote" and
not ecabulated, this is used for probe details.

Because it looks better.

noté en passant

VOID is only valid as a return type. If VOID was used as an argument,
the C compiler would bail out, yet we should better check this early.

Looking through CTYPES, VOID seems to be the only type not valid for
arguments, thus the explicit check.