When a subsystem is disabled, there will be no corresponding object
allocated, and no magic numbers on it.

Like "obsolete" variables, these variables produce a warning when
you try to set them, but the warning says that the relevant module
doesn't have support.

The confdecl macros now have a CONF_CONTEXT that you can define to
make all the modules in a given table disabled.

These modules are only built when the selected modules are disabled.
The provide stub implementations of the subsystem blocks.  Later,
other stub implementations could move here.

Having real subsystem blocks here will let us handle disabled
configuration options better.

This change allows other modules to include confdecl.h without
having first to include integer types they might not even use.

This test doesn't set PYTHON, and ignores USE_PYTHON. And it's already
listed in TEST_SCRIPTS.

Fixes CI issue 32705.

Closes ticket 32732.

Except for src/ext, which we may not want to modify.

Closes ticket 32732.

With v3, the "pending_final_cpath" of a circuit is always NULL which means
that for v3, established client rendezvous circuit waiting for the intro point
to ACK, will always end up timing out quickly.

This can increase the delays to which you connect to a service since in order
to succeed, the rendezvous circuit needs to fully established
(CIRCUIT_PURPOSE_C_REND_JOINED) within the cutoff of the introduction circuit
as well which is these days around 2-3 seconds.

Fixes #32021

Signed-off-by: David Goulet <dgoulet@torproject.org>

"ours" to avoid version bump.

"ours" to avoid version bump.

"ours" to avoid version bump.

They are 0.4.2.5, 0.4.1.7, 0.4.0.6, and 0.3.5.9.

Closes ticket 32704.

"ours" to avoid version bump.

"ours" to avoid version bump.

"ours" to avoid version bump.

"ours" to avoid version bump.