Closes #29391

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

Closes ticket 29436.

It was looking for object files made with the old automake
directorations, but those changed when we split up our libraries.

Fixes bug 29435; bugfix on 0.3.5.1-alpha.

(It was added in 0.3.5)

They have been extracted to a new fallback-scripts.git repository.

Closes ticket 27914.

Closes 29099.

encoding and decoding.

There are bunches of places where we don't want to invest in a full
fuzzer, but we would like to make sure that some string operation
can handle all its possible inputs.  This fuzzer uses the first byte
of its input to decide what to do with the rest of the input.  Right
now, all the possibilities are decoding a string, and seeing whether
it is decodeable.  If it is, we try to re-encode it and do the whole
thing again, to make sure we get the same result.

This turned up a lot of bugs in the key-value parser, and I think it
will help in other cases too.

Closes ticket 28808.

If a relay matches at least one fingerprint, IPv4 address, or IPv6
address in the fallback whitelist, it can become a fallback. This
reduces the work required to keep the list up to date.

Closes ticket 28768.

No behaviour change.

Preparation for 24838.

Cleanup after 28768.

Tor clients on 0.3.5.6-rc? and later will use a consensus that will become
valid up to 24 hours in the future.

Clients on 0.3.5.5-alpha? and earlier won't accept future consensuses.

Update the fallback expiry tolerance to match tor's checks.

Part of 28768, follow-up on 28591.

Tor clients will use a consensus that expired up to 24 hours ago.

Clients on 0.3.5.5-alpha? and earlier won't select guards from an expired
consensus, but they can still bootstrap if they have existing guards.

Update the fallback expiry tolerance to match tor's checks.

Part of 28768, follow-up on 24661.

We can safely silence SC2086 warning on $CHECKERS, as contents of that
is hardcoded into script, and we don't want to require Bash to use Bash
array here. Double-quote $OUTPUTARG, as it's value depends on environment
variable.

This updateVersions.pl script was one of the only essential perl
scripts left in out maint system, and was the only one that used
autoconf to fill in the script.

This script adds a feature to define an APPROX_RELEASE_DATE macro
that is updated when the version changes.  We'll use this to
implement prop297, so that we have an accurate view of when a
release date happens.