We've never really cared how many times the ring buffer has become
empty, how many times data was added to it, or how many times we've
been over the highwater mark.  These have effectively always been
event signalling, with extra hackiness to clear "extra" semaphore
posts.

This commit removes RINGBUF_SEM entirely, and uses events for
everything.  There's an empty event (set when the ring buffer is empty),
a data event (set when the ring buffer is not empty), and a highwater
event (set when the ring buffer has at least highwater mark bytes).

A RingBufWrite() will set data and highwater events if applicable,
and clear the empty event.

A RingBufRead() will set empty event and clear data and highwater
events if applicable.

RingBufReInit() will now set the empty event, and clear the data
and highwater events.

These are the only actions the RingBuf API will perform on the
events, it does *not* clear the highwater event on a RingBufWrite()
if the buffer does not have enough bytes in it for example, this
will *only* be done by RingBufRead() or RingBufReInit().  This
allows consumers to force specific behaviours (such as forcing
the highwater event on shutdown to prevent waiting for it).  Since
the current code was able to deal with the semaphores having
arbitrarily high counts, the existing code shouldn't have any
issue with this.

For things that want to shut something down, we're now setting both
the data and highwater events to ensure it doesn't wait for a
timeout (even for things that don't use highwater like the inbuf).
The RingBuffer API should grow a thing to do this (RingBufferFlush
perhaps?) rather than the consumers poking into the innards
arbitrarily.

Tested on the webserver and RLogin server and seems to be working
great.  sexyz builds.  It seems there's some Windows thing that
uses the ringbuffer sem for something, but I couldn't figure out
what... updated the build file, but no clue if that's broken or not
now... I'm sure DigitalMan will be happy to fix it if CI doesn't
catch it. ;)

This should allow the console object to grow a "flush" method that
will set the highwater and data events.

not scale it in one colour space before translating it to a different
one.

Also, since almost all PPMs will use a maxval of 255, compile that
in as the default so we don't need to generate it.

Update the script to verify pixel operations are supported.

You can copy whole, or portions of a PPM file from the cache directory
to the screen, optionally applying a mask.  The mask can be specified
as a base64-encoded bitmap or as a PBM file in the cache directory.

You can also copy portions of the screen into an internal buffer, and
draw from that internal buffer.  There's plans to support loading an
image file from the cache directory into the buffer as well.

Portions of the buffer can be copied to the screen, optionally
applying a mask as with drawing PPMs.

There's also plans to support copying a PBM file into a mask buffer.

I've added the syncterm-bounce.js script which simply bounces the
SyncTERM icon around the screen like the classic screensaver we all
hate.  I initially wanted to replace the spinning cursor with it,
but there doesn't seem to be a way to replace that with a script. :(

To use the script, just add the text:
@EXEC:syncterm-bounce.js@ to the end of your logon.js script.

Log in to nix.synchro.net with the latest nightly build or build from
git to see the script in action.

the start of wrapped function call continuation lines, but at the
end of struct initializers/enums/etc lines.  I think the least bad
is commas at the end, especially now that it's got the happy
four-space indent for continuations.

I may play with this more later, but this seems to be good for now,
we'll see how it works out in actual use.

I tried a space after too, but that's weird as well and easily
confused with multiplication at first look.

Run uncrustify on this mess.
There's a few small oddities (especially in enums), but this is
much better.

There's no reason to be aggressively ancient.

-b/path/to/bbslist specifies a user BBS list file
-n/path/to/inifile specifies a config file

Remove undocumented -insert option.  This may make nelgin sad, not sure.

... in hopes of debugging issue #468

Also clean up drop files unless -d option is passed.

Incremented version to 0.3.

Not actually part of CTerm, but documented here anyway.

This destroys graphics.  Fixes SF bug 94.

sdl_setwinsize() and eliminate another race.

Pass window size in SDL_USEREVENT_SETVIDMODE
- Fixes race condition where SDL_WINDOWEVENT_RESIZED or
  SDL_WINDOWEVENT_SIZE_CHANGED arraves while
  SDL_USEREVENT_SETVIDMODE is in the queue

Set new scaling based on old scaling multiplier
- Will resize window on mode changes, but tries to keep integer
  multiplier similar.  May break fullscreen modes, dunno.

Have aspect_fix() return higher rather than lower
- This may make it the same as aspect_correct(), but I'm too lazy
  to figure that out.

Add additional stderr debugging.
Don't try to correct the aspect ratio of the window.

Previously, b64_decode was being asked to decode past the end of
the application string.

This should get the original RIP stuff working properly.
LORD icon files are ideally handled a bit differently:
1) If the remote supports the SyncTERM cache operations, icons
   are transferred directly to the cache using them.  This requires
   a SyncTERM build including commit e3a280b6.
2) If LORD is running in-process under Synchronet, it will try to
   initiate a YModem-G download for the files using
   bbs.send_file(name, 'G').  This means YModem-G must be enabled,
   and must use the 'G' command key.

Having the *correct* icon files will still work, but they must be
the expected file size and be the same modified date or newer to
be used by LORD JS.

Ideally, there would be a way to configure sexyz or something to
do icon transfers, but that's a lot harder, so I'm not going to
bother.

Fix off-by-one error with b64 cache store buffer size.

This allows ensuring we don't expand CRLF into CRLFLF.  This is
usually harmless, but there's no real need to put up with it in
a program with a single thread using the expand function.