This doesn't make sense in a world where post-registration SASL is
allowed, and should fix one case of an annoying login desync that's seen
in the real world.
Specifically, when a client sends its final AUTHENTICATE and Atheme
receives it, it sends an SVSLOGIN for that client. If the client sends
us its CAP END *before* we see the SVSLOGIN, the implicit abort will try
to abort the SASL session that's already succeeded.
Atheme interprets this as an instruction to forget about the successful
SASL session; you'll connect unidentified. But it's already sent
SVSLOGIN, which will log the client in ircd-side, causing ircd and
services views to differ until the user authenticates again manually.
I think allowing a SASL session to be aborted when it has already
succeeded is an Atheme bug, and it can still be triggered without this
change. But our behaviour here seems silly anyway.
Quite often people new to Solanum run into trouble in the configure step: the error message if they are lacking either the pkg-config or libsqlite3 packages are identical and discovering the pkg-config dependency is not trivial:
checking for SQLITE... no
configure: error: sqlite3 is required
I can't promise this apt install line is complete, but I know that I've suggested the pkg-config and libsqlite3-dev packages many times in the #solanum channel and they've been very helpful.
Also, ignore a connect block that requests certfp authentication
without setting the ssl flag, as it will then go on to fail anyway.
Finally, correct an erroneous error message about class blocks.
Sadly, this just sends it to purgatory. It's still around for the
socketpair() emulation and the nanosleep() emulation.
socketpair() obviously only selects() on 2 FDs, so not a huge deal.
nanosleep() only uses it for the timeout, so also not a huge deal.
socketpair() is SUSv3 (2001) and nanosleep() is SUSv2 (1997), so maybe
it's OK to remove those emulations. If so, then we can also remove the
sys/select.h check in configure.ac
