Try using INT_MAX, not SOMAXCONN, to set listen() backlog.

Fall back to SOMAXCONN if INT_MAX doesn't work.

We'd like to do this because the actual maximum is overrideable by the
kernel, and the value in the header file might not be right at all.
All implementations I can find out about claim that this is supported.

Fix for 9716; bugfix on every Tor.
Deliver circuit handshake counts as part of the heartbeat

Previously, they went out once an hour, unconditionally.

Fixes 10485; bugfix on 0.2.4.17-rc.
Merge branch 'bug10485_024' into maint-0.2.4
Add a missing include
Some anti-forensics paranoia...

sed -i 's/BN_free/BN_clear_free/g'
changelog for 10793
Merge remote-tracking branch 'public/bug9716_024' into maint-0.2.4
NULL out conns on tlschans when freeing in case channel_run_cleanup() is late; fixes bug 9602
Attribute bug 9602 to a version.
Survive fedora's openssl in our benchmarks

Apparently fedora currently has ECDH but not P224. This isn't a huge
deal, since we no longer use OpenSSL's P224 ever (see #9780 and
72c1e5acfe1c6). But we shouldn't have segfaulting benchmarks really.

Fixes bug 10835; bugfix on 0.2.4.8-alpha.
Make sure orconn->chan gets nulled out when channels exit from channel_free_all() too
Merge remote-tracking branch 'andrea/bug9602' into maint-0.2.4
Merge branch 'maint-0.2.4' into release-0.2.4