(Very) old SLE versions don't have that file at all and we can do
without - we'll just use the previous, default values.

This also means that we don't need to preinstall a package containing
xkbcomp.pc on Debian and derivates for the cleaning target.

Attributes GH PR #735: https://github.com/ArcticaProject/nx-libs/pull/735

Attributes GH PR #717: https://github.com/ArcticaProject/nx-libs/pull/717

This commit + some more adaption in ddxLoad.c which where no longer
present when Alan did the patch. However, our code still has them:

  Author: Alan Coopersmith <alan.coopersmith@oracle.com>
  Date:   Sat Nov 27 20:09:04 2010 -0800

    Convert existing Xprintf style calls to asprintf style
Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>
Reviewed-by: Jeremy Huddleston <jeremyhu@apple.com>
Reviewed-by: Mikhail Gusarov <dottedmag@dottedmag.net>
Backported-to-NX-by: Ulrich Sibiller <uli42@gmx.de>

Author: Pauli Nieminen <ext-pauli.nieminen@nokia.com>
  Date:   Thu Jul 22 11:34:54 2010 +0300

    xkb: Don't check for NULL before calling free
Signed-off-by: Pauli Nieminen <ext-pauli.nieminen@nokia.com>
Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
Backported-to-NX-by: Ulrich Sibiller <uli42@gmx.de>

  Author: Pauli Nieminen <ext-pauli.nieminen@nokia.com>
  Date:   Thu Jul 22 11:33:33 2010 +0300

    xkb: Fix memory leak if opening file fails

    If fopen fails pointer in buf would be overwriten with a new pointer.
Signed-off-by: Pauli Nieminen <ext-pauli.nieminen@nokia.com>
Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
Backported-to-NX-by: Ulrich Sibiller <uli42@gmx.de>

Backported from Xorg:

  commit f292de2ef13dc994a38029cee9e2642576893332
  Author: Daniel Stone <daniel@fooishbar.org>
  Date:   Wed Mar 21 02:04:12 2007 +0200

    XKB: Fix size_syms calculation bug

    Apparently it needed to be nSyms*15/10, not *12/10; make it match the
        other allocation code.
Backported-to-nx-by: Ulrich Sibiller <uli42@gmx.de>

    commit 7c4c00649cae855e141ec9a3667bfe399e3156d0
    Author: Daniel Stone <daniel@fooishbar.org>
    Date:   Thu Jan 1 05:25:52 2009 +1100

        XKB: Remove unused DDX functions

        They were complete no-ops anyway.
Signed-off-by: Daniel Stone <daniel@fooishbar.org>
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Backported-to-nx-by: Ulrich Sibiller <uli42@gmx.de>

    commit 6aef4e96affcc26b9415c6bc9c9bebb5af05a1a7
    Author: Daniel Stone <daniel@fooishbar.org>
    Date:   Sat Jan 17 13:42:46 2009 +0200

        XKB: Fix logic error

        Use logical or instead of bitwise or.
Signed-off-by: Daniel Stone <daniel@fooishbar.org>
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Backported-to-nx-by: Ulrich Sibiller <uli42@gmx.de>

  commit 8311cd5f89ca6781842bb24671b8122cdf8be148
  Author: Jeremy Huddleston <jeremyhu@freedesktop.org>
  Date:   Tue Mar 23 10:37:36 2010 -0700

      XKB: Fix garbage initialization

      XkbEnableDisableControls set extra garbage bits on the xkbControlsNotify
          changedControls mask because it was uninitialized on the stack.

      Found by clang
Signed-off-by: Jeremy Huddleston <jeremyhu@apple.com>
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Backported-to-nx-by: Ulrich Sibiller <uli42@gmx.de>

  We have fixed that (independendly) before, but missed one line.
Backported-to-nx-by: Ulrich Sibiller <uli42@gmx.de>

    commit 85f9017393c9bb19553e9afcf554673a44a09993
    Author: Ander Conselvan de Oliveira <ander.conselvan-de-oliveira@nokia.com>
    Date:   Tue Feb 8 11:10:10 2011 +0200

      ProcXkbGetXkbByName: fix use of uninitialised bytes valgrind error.

      ==9999== Syscall param writev(vector[...]) points to uninitialised byte(s)
      ==9999==    at 0x4AB5154: writev (writev.c:51)
      ==9999==    by 0x7C7C3: _XSERVTransWritev (Xtrans.c:912)
      ==9999==    by 0x61C8B: FlushClient (io.c:924)
      ==9999==    by 0x62423: WriteToClient (io.c:846)
      ==9999==    by 0xCE39B: XkbSendMap (xkb.c:1408)
      ==9999==    by 0xD247B: ProcXkbGetKbdByName (xkb.c:5814)
      ==9999==    by 0x4AB53: Dispatch (dispatch.c:432)
      ==9999==    by 0x205BF: main (main.c:291)
      ==9999==  Address 0x557eb68 is 40 bytes inside a block of size 4,096 alloc'd
      ==9999==    at 0x48334A4: calloc (vg_replace_malloc.c:467)
      ==9999==    by 0x62567: WriteToClient (io.c:1065)
      ==9999==    by 0x452EB: ProcEstablishConnection (dispatch.c:3685)
      ==9999==    by 0x4AB53: Dispatch (dispatch.c:432)
      ==9999==    by 0x205BF: main (main.c:291)
      ==9999==  Uninitialised value was created by a stack allocation
      ==9999==    at 0xD1910: ProcXkbGetKbdByName (xkb.c:5559)
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Reviewed-by: Oliver McFadden <oliver.mcfadden@nokia.com>
Signed-off-by: Ander Conselvan de Oliveira <ander.conselvan-de-oliveira@nokia.com>

Backported-to-nx-by: Ulrich Sibiller <uli42@gmx.de>

    commit 8a34d7a8532c7ca013e67307f3baf200167abb92
    Author: Ander Conselvan de Oliveira <ander.conselvan-de-oliveira@nokia.com>
    Date:   Tue Feb 8 11:10:11 2011 +0200

      XkbSendNames: fix use of uninitialised bytes valgrind error.

      ==537== Syscall param writev(vector[...]) points to uninitialised byte(s)
      ==537==    at 0x4AB7154: writev (writev.c:51)
      ==537==    by 0x8935B: _XSERVTransWritev (Xtrans.c:912)
      ==537==    by 0x6C55F: FlushClient (io.c:924)
      ==537==    by 0x6CCF3: WriteToClient (io.c:846)
      ==537==    by 0xD51D3: XkbSendNames (xkb.c:3765)
      ==537==    by 0xD8183: ProcXkbGetKbdByName (xkb.c:5825)
      ==537==    by 0x27B7B: Dispatch (dispatch.c:432)
      ==537==    by 0x205B7: main (main.c:291)
      ==537==  Address 0x55899f2 is 154 bytes inside a block of size 1,896 alloc'd
      ==537==    at 0x4834C48: malloc (vg_replace_malloc.c:236)
      ==537==    by 0xD47AF: XkbSendNames (xkb.c:3642)
      ==537==    by 0xD8183: ProcXkbGetKbdByName (xkb.c:5825)
      ==537==    by 0x27B7B: Dispatch (dispatch.c:432)
      ==537==    by 0x205B7: main (main.c:291)
      ==537==  Uninitialised value was created by a heap allocation
      ==537==    at 0x4834C48: malloc (vg_replace_malloc.c:236)
      ==537==    by 0xD47AF: XkbSendNames (xkb.c:3642)
      ==537==    by 0xD8183: ProcXkbGetKbdByName (xkb.c:5825)
      ==537==    by 0x27B7B: Dispatch (dispatch.c:432)
      ==537==    by 0x205B7: main (main.c:291)
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Reviewed-by: Oliver McFadden <oliver.mcfadden@nokia.com>
Signed-off-by: Ander Conselvan de Oliveira <ander.conselvan-de-oliveira@nokia.com>

an empty nxagentKeyboard variable is no reason to fall back to no-XKB mode

most of the code was existing twice

manpage does not tell us if NULL is valid

use the ones from xkb

Just use the existing xkb code

Defines regarding XKB-BASE_DIRECTORY are used only xkb.

Attributes GH PR #734: https://github.com/ArcticaProject/nx-libs/pull/734

Attributes GH PR #732: https://github.com/ArcticaProject/nx-libs/pull/732