VRT_MINOR_VERSION needs to be incremented for the 4.1 branch.

Original test case by fgsch

Fixes: #1858

Pointed out by nirn on irc.

This keeps the increment and decrement in the same compilation unit.

n_objectcore is incremented by ObjNew(), so HSH_Insert() should not
increase it again.

HSH_Insert() needs to take the same precautions as HSH_Unbusy() in
order to not race against e.g. the ban lurker. In order to do this, we
pass it the ban that the objcore should be associated with, and it
will take care of calling BAN_RefBan() correctly.

BAN_FindBan looks up a ban based on a ban timestamp and returns a
pointer to the ban. Returns NULL if no ban with that timestamp is
present.

BAN_RefBan takes an objcore and a ban. It grabs a reference to the ban
and associates the objcore with that ban.

Fixed size attributes has it's space always reserved.

Variable size attributes change in size, and their combined total
length needs to be given to allocobj.

Auxiliary attributes do not need to be predeclared.

The code for setting and getting the attributes is generated from a
table that lists the different attributes according to their type.

Add documentation about the behaviour of the get/set functions.

This is to make it clear that one can not change an object attribute
through the returned pointer from ObjGetattr()

The objcore won't gain a boc in a way that would call for locking the
OH when checking if it wasn't there in the first place. So if the
oc->boc is NULL, return early. This saves a mutex lock/unlock in the
common case.

only once, once we know it.

This allows Martin to stash attributes on going into BOS_STREAM.

a request for zero bytes.

Suggested by:	github::onovy

This has been available via the std module for some time now.
OK'd by phk@.

Autotools stuff is kept out of the picture, except pkg-config(1) which
is essential for testing foreign code against a fresh Varnish build.

Parameters are not checked and passed as is to varnishd command lines.
The parameters are prepended at the beginning of the command line to
preserve parameters needed by varnishtest or used in test cases.

The macros are still here but ${vmod_std} is now expanded to std and so
on.

Instead, varnishtest users should set up a proper PATH, just like
`varnishtest -i` does to use binaries from the build tree.

The former are kept for backward compatibility as aliases for now.
While here update some related doc and remove dead code.