Avoid duplication, and add logging for some more error conditions so
it's possible to see in the logs why a resize has failed or produced
unexpected results.

The generally recommended way is to include it from source files, not
headers. We had a mix of both. Let's try to be consistent and follow the
recommended way.

Some operating systems such as FreeBSD don't define a HOST_NAME_MAX
macro. The portable approach to determine the real host name limit is
calling sysconf(_SC_HOST_NAME_MAX) so do that instead.

We miscalculated the screen layout if the geometry had an offset as we
adjusted the real screen layout to account for the offset, but compared
it to the unadjusted geometry.

Is a lot more useful default than the previous "x11", or "x0vncserver".
At the same time give x0vncserver a parameter to change the name.

Better to just hide these parameters rather than stating that they are
unused in the man page.

Trying to dynamically track the DPI did not really work as we'd
start accumulating errors and eventually the DPI would start to
drift. Instead maintain a fixed, sensible DPI at all times.

This change adds support for the VMware Mouse Position
pseudo-encoding[1], which is used to notify VNC clients when X11 clients
call `XWarpPointer()`[2]. This function is called by SDL (and other
similar libraries)  when they detect that the server does not support
native relative motion, like some RFB clients.

With this, RFB clients can choose to adjust the local cursor position
under certain circumstances to match what the server has set. For
instance, if pointer lock has been enabled on the client's machine and
the cursor is not being drawn locally, the local position of the cursor
is irrelevant, so the RFB client can use what the server sends as the
canonical absolute position of the cursor. This ultimately enables the
possibility of games (especially FPS games) to behave how users expect
(if the clients implement the corresponding change).

Part of: #619

1: https://github.com/rfbproto/rfbproto/blob/master/rfbproto.rst#vmware-cursor-position-pseudo-encoding
2: https://tronche.com/gui/x/xlib/input/XWarpPointer.html
3: https://hg.libsdl.org/SDL/file/28e3b60e2131/src/events/SDL_mouse.c#l804

Setting `rfbport` to `-1` disables TCP port listening.

Mainly fixes for Japanese and Korean keyboard layouts.

Major restructuring of how streams work. Neither input nor output
streams are now blocking. This avoids stalling the rest of the client or
server when a peer is slow or unresponsive.

Note that this puts an extra burden on users of streams to make sure
they are allowed to do their work once the underlying transports are
ready (e.g. monitoring fds).

External callers don't need to know the exact details, only if there is
data that needs to be flushed or not.

This makes our builds directly compatible with most distributions
without packagers/users having to specify extra flags.

Don't allow subclasses to just override dimensions or buffer details
directly and instead force them to go via methods. This allows us
to do sanity checks on the new values and catch bugs and attacks.

We now filter incoming data, which means we can start assuming the
clipboard data is always null terminated. This allows us to clean
up a lot of the internal handling.

There might be multiple clients using a single IP (e.g. NAT), which
can make the blacklist do more harm than good. So add a setting to
disable it if needed.

Patch originally by @KenMilmore on GitHub.

Add more checks and fix some callers to make sure that the server
core always has a valid screen layout configured.

It now accepts this parameter, so make sure it is documented.

We disabled it in 0a0e582 since it didn't have support for resizing.
But it got that support in 242c5b2, yet we forgot to allow this
setting again.

It doesn't belong on each socket server object as timers are global.
Force implementations to call the Timer system directly instead,
avoiding any middle men.

Do a proper cleanup when one of the termination timeouts trigger
rather than just exiting on the spot. This makes sure we don't leave
stray stuff around, e.g. unix socket files.

We might have an offset in the area of the screen we're tracking,
so make sure that offset is included in the changes we report.

We might only be using part of the X server's screen, so make sure
the layout we calculate is contained within this part.

This makes VNCServer a sufficiently complete interface that callers
don't need to know about the specific implementation (VNCServerST
currently). And assuming that all servers will use sockets is not
that outrageous.

Removed the last parts of VNCSConnectionST's back door in to
VNCServerST and let the parent class fully handle coordination of
clients, and access to the desktop.

Must be done in order to remove UNIX sockets etc.

Our main web site now supports https, so update all references.

Make things simpler by making this a part of the SDesktop interface
that always needs to be implemented.

Force queryConnection() to always call back to approveConnection()
rather than return special values. This makes the flow easier to
follow as it will be the same in all cases.

We cannot assume endian-ness for the cursor we get from XFixes.
Adjust the algorithm to properly follow the specification.

There are some cases where the server state will not automatically
be updated on a change. A prominent one is when only RFB attributes
were changes (e.g. the screen ID) but nothing else. In that case
there is no actual change in the X server, so it never sends any
notification about change back to us.

x0vncserver might only be observing part of the display, so we need
to adjust any coordinates before we give them to the RFB core.

The Xserver (at least Xorg 1.19) rejects RRSetCrtcConfig requests if
rotation is zero.

Makes the code more general and not directly tied to specifically
TCP sockets.

Change Xserver screen through libXrandr. For complex configurations,
all outputs must have corresponding size modes. As a special case, if
the client requests a single screen with an odd size (for example when
adjusting the size of a non-fullscreen vncviewer), find a smaller
suitable mode, and reduce the framebuffer size as well.

It wasn't properly updated in 3112f50 when it was split off from
x0vncserver.cxx.

In XDesktop::start() we allocate pixel buffer and set it as the backend to the given VNCServer.
In XDesktop::stop() we deallocate the buffer, so we must unset it from the VNCServer as well.
Otherwise the VNCServer could try to access it and crash, for example in deferred update.

Colour map support was removed in b6b4dc6, but x0vncserver didn't
properly check if the X server required it.

There were a bunch of parameters that weren't properly added to the
man pages when the features were added. Make sure everything is
properly in sync.

They share a lot of settings, so make sure the documentation is
identical in those cases.

The funcationality was removed in 6e49e95, so let's also clean up
the documentation referring to it.

XShmGetImage is much faster. On my machine, this reduces the CPU usage
of a fullscreen Youtube video playback from 40% to 25%.