Poll update

See merge request !116

Still needs updates in services_thread(), CGI stuff in websrvr.c,
and sbbs_t::external()

Found by digging through headers... Apple doesn't document this.

Just some more macOS silliness.

Sometimes the comment wasn't redrawn.
Also, remove configurable mouse actions stuff, not implemented in
13 years, I suspect I'll never do it.

While they both delete a character, delete at the end of a line will
move the next line up instead of moving this line up.

Fixes #243

Just in case it was read as a string (e.g. had a ; comment following the value)

caused it to be represented as JS string rather than number causing an issue
with login.js:
Node 1 terminal not detected, reducing inactivity hang-up timeout to 0 seconds

Redraw map before returning to startma/startma1

There's likely an ass-ton of these though.

Also check bbs.online for sbbs input.

Synchronet goes boom.

When a players map is set, it automatically triggers a player record
write.  When a new player is being created, the map is set before
the player is added via @addchar.

This attempted to write record number undefined in the player file,
which threw an exception.  Since exceptions are being caught, logged,
and ignored, this did not cause a problem, but did log an error when
it wasn't necessary.

This should never actually be done though since the map would be
completely empty.

Prevents a who's online list from aborting early when it encounters
and invalid player record.

Used by gcc in warnings.

If a '\r' is the last thing in the previous receive buffer.

Not all implementations set POLLHUP when a TCP socket is half-closed.

Was returning disconnected when it wasn't at times.

This likely unbreaks the things.

A socket isn't bad just because there was no incoming connections. :D

This won't impact Synchronet as it has a separate signal handling
thread, but we still need to behave properly for processes that
don't.  I'm also saying that ENOMEM does not indicate a disconnection,
though it may be better to pretend it was disconnected...

socket_readable() returns TRUE if recv() will not block if called
on the specified socket.

socket_writable() returns TRUE if send() will not block if called
on the specified socket.

socket_recvdone() returns TRUE if all data has been recv()ed an
the socket is closed.

"will not block" includes "will return an error".

This matches the three main use-cases for select() of a single socket
in Synchronet.

Use them in the SyncTERM RLogin stuff so they can be tested easily.

MinGW32 is getting long in the tooth and is missing a lot of modern
Windows features as well as having broken headers.  Most people will
be using MinGW-w64 at this point, so add support for it.  Once I
ensure SyncTERM works properly with it, MinGW32 support will be
discontinued.

I suspect this will impact exactly zero people since the reason this
exists is to build the Win32 versions of SyncTERM on FreeBSD.

Changes:
- Explicitly request 32-bit Windows output
- Detect the string "mingw32" anywhere in the hardware description
- Explicitly link with libuuid
- Add a terrible hack to syncterm.c to block wincrypt.h

Do not clear at the current X/Y on scroll (derp)

Scrolling would clear the line to the end of the screen, not the
end of the scrolling region.

Sorry echicken.

Could be useful for knowing if you need to increase MaxClients for typical
usage.