Switch from using Core events to using X Input events for pointer
devices in order to differentiate between mouse events and touch events.

Because FLTK doesn't understand X Input 2, we intercept these events and
translate them to core events where possible.

We need to make sure everything happens in the correct order during
startup for the X11 display to open correctly. Primarily it means
we need to parse the arguments and open the display before anything
might make any X11 calls, as we may have a -display argument.

We don't exit here, so it's not a fatal error. It's also a fairly common
scenario, so remove the alert completely.

Makes things more consistent and avoids surprises.

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

We need to make sure it is null terminated on truncation. We also
need to avoid giving a too large size argument or modern gcc will
complain.

It's not common knowledge these days how X geometry is specified, and
even the man page X(7) is missing on many systems now.

FLTK has some options (that we've also documented in the man page)
that should be mentioned in the --help output.

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

We've had support for unix sockets for a while now. Make sure this
is reflected in the -help output and the man page.

Also make some minor tweaks to the section to get everything in
sync with reality.

We might not get one from the default configuration (we might not have
a default configuration at all), so make things more robust.

The user might just want to load a bunch of settings and not
initiate a connection.

The user can specify a tigervnc configuration file as an argument to the
viewer. Previously the viewer assumed this to be a server, but now we
will first check if there is any file matching the given argument. If
so, try to load the content of that file, like we normally do.

Fixes issue #38.

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

Fl::arg accepts several arguments which we are not documenting. Also,
it accepts a -geometry argument, which clashes with our own -geometry
option.

macOS no longer uses the old Aqua look, so tweak our things to fit
in better with the current state of things.

E.g. vncviewer server.example.com:2 -display :2

We have to wait until we've passed the command line arguments or
we might overlook a -display argument.

Add a new parameter 'alertOnFatalError' which guards
the displaying of the GUI alert on fatal errors, and
thus when false just gives the textual error.

Now I can do:

  while true
  do
    vncviewer alertOnFatalError=false vm:0
    sleep 1
  done

and it'll reappear when my VM appears without me getting error
dialogs.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
--

It is easier to control object life time and avoid magical socket
duplication by having a single TcpListener object to pass around.
We have to be more careful about deleting the object though.

Makes it easier to see which hot-keys might conflict with each
other, and allow some variation in translation in the future.

It should be possible to exit the viewer even if the network has
stalled in the middle of a transfer.

It doesn't really make sense anymore given that settings might come
from the GUI or configuration and not only the command line.

It was actually a feature to translate the about string multiple
times as we may need different character encodings for it. We
still want a better approach that allows the compiler to analyse
the format string though so it isn't just a simple revert.

The TcpListener constructor now takes a 'struct sockaddr*' instead of
a string, and the createTcpListeners function creates TcpListener
instances for an address based on the results from getaddrinfo().

The XserverDesktop class now takes a list of TcpListener instances for
each of the RFB and HTTP sockets.

The TcpListener::closeFd member variable is not used and has been
removed.

In earlier Visual Studio and MinGW editions, BSD socket errno:s were
left undefined. This is no longer the case. This may cause build or
runtime errors. To avoid this, we are using a common header file which
corrects all definitions. This header will also be used with other
projects such as sercd, unfs3, PulseAudio etc.

This means that we can remove a lot of conditionals and fallback code.