In preparation for the next commit, we avoid using the ctx->msg vsl and
use a separate vsl for the VCL_Open step of vcl_load.

Ref #2902

vcl_event dictates ctx->method, so we set it where we need it.

Note: This is in preparation of the disabled AZ(ctx->msg) for cold
events, but we are not there yet.

Ref #2902

I have a plan to help them fit in the table, and regrouping them will
make matters simpler.

Much better diff with the --patience option.

It was already gone for the 4.1.0 release, replaced by the varnishd -W
option.

And with that trailing zero-flags can be omitted.

It turns out it's not just minimum and maximum values that can be
dynamic.

It's a bit weird that the default value and the unit is separated from
the min and max. This aligns struct parspec field order with the PARAM()
macro for these two fields.

In static parspec definitions, the flags field can now be omitted if
there are no flags, and the parameter is not subject to dynamic bounds.

I didn't change their shorthand counterparts (for example st for s-text)
because they will go away soon enough.

Now that PARAM() is a vararg macro, we can afford having the dynamic
bounds reasons only for relevant parameters without bloating the rest
of the table.

The two places where the parameters table is used have very distinct
needs, and even among parameters themselves we will need some degree
variation.

This is the first of a series of mechanical patches made possible by vim
macros. This is a first step towards continuing the work initiated in
39e0bc53 and the first observation is that we have some dead weight
in the table.

This was documented following the naming convention in tree, but
implemented differently. In order not to change the behavior, only
the documentation is updated.

Closes #3232

fixes #3229

When doing a pass, we would remove the Age header from the backend, and
create a new one based on the time the fetch was initiated. This creates
problems when calculating the time to live in downstream caches (browser
cache or layered varnishes).

With this patch, the RFC_2616_Ttl calculation routine is run also for
passes, where the t_origin field of the object is adjusted for an incoming
Age header. This makes sure that the Age header generated during delivery
is correct. The rest of the Ttl calculation is skipped for passes,
including the logging of SLT_TTL "RFC".

Fixes: varnishcache/varnish-cache#3221

One time element function to rule and parse them all.

Change the return value to unsigned, to match with the expected data type
where it is used.

Handle very large numbers consistently. Currently it was converting from
unsigned long to int, which would throw away the most significant
bits. Now overly large integers will be capped at UINT_MAX.

Implement the "allow and ignore decimal point" behaviour that the Age
header parsing incorporated in rfc2616_time(). This way we will allow a
decimal points also in max-age and stale-while-revalidate parsing of
Cache-Control directives.

Better diff with the --word-diff option.

We have two fallbacks in the absence of a .host_header field in the
backend, one of which is systematic. We can build a non .request probe
request with a single printf statement.

Please note that when the .host field is in the form "$addr $port" we
use that as the probe's host header. This behavior is not introduced by
this change but ultimately we might want to do something about it and
for example capture the first token from hosthdr with a txt.

In case of failure, I can see which client failed more easily.

rest of our test-programs are structured.

A lot of this is s/REQ_BODY_/BS_/g, followed by a reduction
pass to go from testing on specific status values to attributes
of the status value.

For instance the req.body caching code does not need to know if
how the transport sees this, chunked vs. eof for instance, it just
needs to know that there is a body and that we do not know the
length of it yet.

The transports own the "vocabulary", because internally H1 needs
to know the difference between BS_CHUNKED and BS_EOF in order to
setup the VFPs.

This worked only because REQ_BODY_INIT = 0

I hate C enums.

This reverts commit 54e7d45b.

However instead of reverting to the previous domain, I picked a
different one that I hope will not turn out controversial.