Backport of this xorg-xserver patch:

  commit 3083c5d0c4386cdd7083b7a83ac72fdad2f1e61e
  Author: Michel Dänzer <daenzer@vmware.com>
  Date:   Mon Mar 22 18:01:17 2010 +0100

    Xext: Fix cursor reference counting hazard.

    Make sure the reference count of the new cursor is increased before the old
    one is decreased, otherwise bad things will happen if they're one and the
    same and the reference count is 1 initially. Not sure this can actually happen
    here, but better safe than sorry.
Signed-off-by: Michel Dänzer <daenzer@vmware.com>
Reviewed-by: Roland Scheidegger <sroland@vmware.com>
Signed-off-by: Keith Packard <keithp@keithp.com>

(from nxagent changelog)

It is better to create the values array once and not on every iteration..

Does not require two parameters. It could be replaced by
RegionDestroy() entirely but we leave it to have a match to
nxagentCreateRegion().

Now all cleanup code at the end of the function is gone so there's no
need for the gotos anymore. Just return directly.

move common code into helper function that also takes care of the ugly
alloc/free stuff.

Otherwise we will never be able to free the list because we do not know
if free() is allowed or not.

add else clauses, improve debugging, add comments

not a real memleak since it is followed by a FatalError...

The FIXME just described what the following function actually implements...

Attributes GH PR #922: https://github.com/ArcticaProject/nx-libs/pull/922

if neither NX_CLIENT ist provided nor /usr/NX/bin/nxclient is existing
try /usr/bin/nxdialog.

Currently the path is hardcoded.

Attributes GH PR #917: https://github.com/ArcticaProject/nx-libs/pull/917

The changes are either applied in the current version or the affected
file is no longer existing.

We have never built nxwin within this tree. And we never shipped
it. So drop the according logic.

We have also removed CYGWIN stuff in the past so nxwin probably would
not compile/work anyway...

Attributes GH PR #899: https://github.com/ArcticaProject/nx-libs/pull/899

We have no hardware that could blank the screen for us. So let
nxagentSaveScreen return False in some situations to let dix do the
default action.

we moved the auto-disconnect feature to an own timer so there's no
need for a special treatment in screen saver stuff anymore.

Option -timeout used the screensaver facility. This patch changes that
to an own timer that is independent. This effectly means we can drop
most of the derived screensaving stuff in a follow-up commit.

Attributes GH PR #895: https://github.com/ArcticaProject/nx-libs/pull/895

This was removed by mistake in 39866f5c.

Fixes ArcticaProject/nx-libs#904

Clean.c: In function ‘CleanZImage’:
Clean.c:141:23: warning: declaration of ‘j’ shadows a previous local [-Wshadow=local]
       register int i, j;
                       ^
Clean.c:88:16: note: shadowed declaration is here
   unsigned int j;
                ^
Clean.c: In function ‘CopyAndCleanImage’:
Clean.c:239:22: warning: declaration of ‘i’ shadows a previous local [-Wshadow=compatible-local]
         register int i;
                      ^
Clean.c:192:16: note: shadowed declaration is here
   register int i;
                ^
Clean.c:324:13: warning: declaration of ‘i’ shadows a previous local [-Wshadow=compatible-local]
         int i;
             ^
Clean.c:192:16: note: shadowed declaration is here
   register int i;
                ^

  commit 08d0481e299c28b64a0db9bb0782ba2b551028fd
  Author: Keith Packard <keithp@keithp.com>
  Date:   Sun Dec 15 01:12:22 2013 -0800

    os: Fix -Wshadow errors

    Rename variables to avoid shadowing globals
Signed-off-by: Keith Packard <keithp@keithp.com>
Reviewed-by: Eric Anholt <eric@anholt.net>