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.

Otherwise things might be logged under the wrong label.

There is no such thing as XDG_DESKTOP_NAMES.

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.

VENDOR_STRING is gone as is DEFAULT_LOG_VERBOSITY
site.h has been removed and is not needed.

This fixes regression introduced by the extended clipboard extension.
Previously it was possible for the server to hold on to the CLIPBOARD
selection even if another application took ownership of PRIMARY. This is
important to handle the common use case of selecting something in order
to paste over it.

The new request based model doesn't readily support this as we assume
the client has lost its data once we push the new PRIMARY selection to
it. So to handle this we have the maintain a cache of the client's data,
and make sure to fill that cache before we do anything that might cause
the client to lose the data.

I am cross-compiling from macOS for a FreeBSD-derived system so my host
file system is case insensitive but the target isn't. Without this change
I get the following warnings which show that the vnc "Input.h" is being
included from mi/mi.h instead of the xserver "input.h":
```
In file included from /Users/alex/cheri/xvnc-server/hw/vnc/Input.c:33:
/Users/alex/cheri/xvnc-server/mi/mi.h:55:10: warning: non-portable path to file '"Input.h"'; specified path differs in case from file name on disk [-Wnonportable-include-path]
#include "input.h"
         ^~~~~~~~~
         "Input.h"
```

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.

Xvnc was originally based on Xvfb, but it's just confusing to keep the
names. So change all prefix to "vnc" instead to clearly mark things as
part of TigerVNC.

It isn't really useful as it behaves just like starting multiple
servers, so remove it in favour of keeping things simple.

This is a development flag with no real use, so remove it to clean up
the code.

Remove stuff we don't use, and get it more in sync with Xvfb for easier
comparison.

This was removed years ago.

The memory leak this worked around was fixed in X.org 1.16.

Keep everything in one place to make it easier to read.

This also removes the call to RRInit() as that is done implicitly
anyway.

There's been a common one since X.org 1.11, so use that instead of our
own copy.

We don't build for that platform anyway, so this is just a remnant from
Xvfb.

With the 1.20.x releases there has been features and API changes even on
patch level versions, so we need to update our macros to handle these as
well.

This is a pointless remnant of Xvfb. We never print the id of the shared
memory, so no other application can access this memory anyway.

This hasn't been supported or used in many years, so clean out the final
remnants.

This hasn't been used since xorg-server 1.1 so get rid of it.

This is consistent with other ddx behaviour.

This is what all the other ddx variants use, so do the same in Xvnc to
be consistent.

Makes it easier to compare with upstream files as the formatting will be
the same.

RENDER has been mandatory since xorg-server 1.9, so remove these
checks.

This should only be in the ddx parts of an X server, and Input.c is used
by libvnc.so as well and can cause conflicts there.

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.

Give people a chance to know about the documentation.

It's almost mandatory to specify "session", but fairly rare to need to
set "desktop", so let's tweak the examples to avoid confusion and
mistakes.

The new vnc_home_t type for HOME/.vnc directory was added to the policy,
backed by a name transition. The vnc_session_t domain can manage files
and directories of this type.

The permissions set to manage directories and files with the nfs_t type
is allowed when the use_nfs_home_dirs boolean is turned on.

Resolves: https://github.com/TigerVNC/tigervnc/issues/1189

Sections and rules blocks reordered according to the Style guide.

https://github.com/TresysTechnology/refpolicy/wiki/StyleGuide

Style guide [1] issues only. No impact on policy functionality.

[1] - https://github.com/TresysTechnology/refpolicy/wiki/StyleGuide

Build flags control where this file ends up, so avoid assuming a
specific path in the HOWTO.

The line width was very inconsitent in this file, so standardise on the
common 72 characters.