This also solves the last remnant of overlinking as described in GH issue #133.

 Fixes ArcticaProject/nx-libs#133.

git-subtree-dir: nx-X11/extras/Mesa_6.4.2
git-subtree-split: 475b1f7b56fa36ef4f3b22a749f88a98ddc0d502

git-subtree-dir: nx-X11/extras/Mesa_6.4.1
git-subtree-split: 53d1bc081eb633aecbd5ab0bf3981f734a2102f2

When descending subdirectories and calling configure pass
`--prefix=${DESTDIR}${PREFIX}`, so that installing in a
custom directory works.

Makefile: Make sure that 'make all' only calls 'make build' and _not_ the global '%:' ruleset afterwards.

 - Move FONT_DEFINES and XLIBFONT definition to from Server.tmpl to
   Imake.tmpl.
 - Add FONT_DEFINES to ALLDEFINES.
 - Drop SpecialCObjectRules with FONT_DEFINES from various Imakefiles
   again, FONT_DEFINES is now set "globally".
 - Hand over FONT_DEFINES from main Makefile to nx-X11's make BuildEnv
   to make gccmakedep happy.

Makefile: Tell Xserver build which Xfont API to use (v2 or v1) depending on what's available in the build env.

Xserver/os/oscolor.c: Follow X.org in dropping the rgb.txt file entirely. Content of that file is now hard-coded.

 Adopting an exact copy of os/oscolor.c from X.org leads to this compiler warning:

 ```
 oscolor.c:844:1: warning: string length ‘7614’ is greater than the length ‘4095’ ISO C99 compilers are required to support [-Woverlength-strings]
 };
 ^
 ```

 This will be address later in coordination with X.org.

 Note: there is a tiny change in oscolor.c as we ship it. The original X.org file includes <X11/keysym.h> which seems
 unneeded. We drop that one line from oscolor.c.

 Fixes ArcticaProject/nx-libs#259.

Makefile: Fix flawed uninstall-* targets. Spotted by Ionic while reviewing the nxagent RPATH changeset. Thanks!

  SHLIBDIR -> Points to the system's official library folder.
  USRLIBDIR -> In NX, this variable (amongst others) is used to set
               the executables RPATH (if enabled), so pointing this
               to SHLIBDIR/nx-X11.

Makefile: Align variable names USRLIBDIR, SHLIBDIR (and NX_DIR) with nx-X11 internal naming schemes (and use /usr/<lib>/nx/X11 rather than /usr/<lib>/nx-X11).

Xserver/os/oscolor.c: Follow X.org in dropping the rgb.txt file entirely. Content of that file is now hard-coded.

 Adopting an exact copy of os/oscolor.c from X.org leads to this compiler warning:

 ```
 oscolor.c:844:1: warning: string length ‘7614’ is greater than the length ‘4095’ ISO C99 compilers are required to support [-Woverlength-strings]
 };
 ^
 ```

 This will be address later in coordination with X.org.

 Note: there is a tiny change in oscolor.c as we ship it. The original X.org file includes <X11/keysym.h> which seems
 unneeded. We drop that one line from oscolor.c.

 Fixes ArcticaProject/nx-libs#259.

Makefile: Fix flawed uninstall-* targets. Spotted by Ionic while reviewing the nxagent RPATH changeset. Thanks!

  SHLIBDIR -> Points to the system's official library folder.
  USRLIBDIR -> In NX, this variable (amongst others) is used to set
               the executables RPATH (if enabled), so pointing this
               to SHLIBDIR/nx-X11.

Makefile: Align variable names USRLIBDIR, SHLIBDIR (and NX_DIR) with nx-X11 internal naming schemes (and use /usr/<lib>/nx/X11 rather than /usr/<lib>/nx-X11).

Makefile: Don't create superfluous symlink for libX11.so -> ../libNX_X11.so. The libNX_X11.so is only required at build time, so need to use it for faking libX11.so in nxagent.

 Fixes ArcticaProject/nx-libs#286.

 Fixes ArcticaProject/nx-libs#276.

`readlink` returns nothing for non-symlinks. Careful investigation of the build
environment revealed that libNX_X11.so.6.2 was no symlink to begin with - so
the whole copy operation failed.

Pro-actively fix the call though, in case we ever encounter a symlink there.

Makefile: Make sure libNX_X11.so.6.2 does not get installed as symlink but as actual file. (Follow-up for 5a90a638).

Makefile: Adapt install target to the new situation where we fake X11 headers in .build-export. This fixes FTBFS during file installation into .deb and .rpm packages.

  - Update XErrorDB to latest X.org version.
  - Install XErrorDB, XKeysymDB and Xcms.txt to /usr/{local/}share/nx/.
  - Assure that libNX_X11 finds those files at the
    named location.
  - Update debian/ packaging files.
  - Update nx-libs.spec packaging file.

Fixes ArcticaProject/nx-libs#153

  o Install nxagent/nxproxy executables into multi-arch path.
  o Fake libNX_X11.so* as $LIBDIR/nx-X11/libX11.so*.
  o Allow injecting different $NXAPP containing the executable name.

  o For e.g. x2goagent this requires the following changes:

    - Move x2goagent symlink from /usr/lib/x2go/bin/x2goagent to
      $LIBDIR/nx/bin/x2goagent
    - Replace /usr/bin/x2goagent by a two-liner...

    ```
    #!/bin/sh

    export NXAPP=x2goagent
    nxagent
    ```

 Note:

  - The "normal" way to inject CFLAGS (and CPPFLAGS) into nx-X11 builds is copying those
    options over into the variable CDEBUGFLAGS.
  - LDFLAGS have to be handed to nx-X11 via LOCAL_LDFLAGS.

 This change also includes a slight change in the nx-X11 build order.

 Old build order:

  Main Makefile:

      - [...]
      - libNX_X11
        + implicitly building nxcomp
        + implicitly building nxcompext
      - [...]
      - nxagent
        + implicitly building nxcompshad
      - [...]

 New build ordner:

  Main Makefile:

      - [...]
      - nxcomp
      - setup nx-X11 build env
        + cd nx-X11 && make BuildEnv
      - nx-X11/lib/*
      - nxcompext
      - nxcompshad
      - [...]
      - nxagent
      - [...]

 Fixes ArcticaProject/nx-libs#141
 Fixes X2GoBTS#84

 Note:

  - The "normal" way to inject CFLAGS (and CPPFLAGS) into nx-X11 builds is copying those
    options over into the variable CDEBUGFLAGS.
  - LDFLAGS have to be handed to nx-X11 via LOCAL_LDFLAGS.

 This change also includes a slight change in the nx-X11 build order.

 Old build order:

  Main Makefile:

      - [...]
      - libNX_X11
        + implicitly building nxcomp
        + implicitly building nxcompext
      - [...]
      - nxagent
        + implicitly building nxcompshad
      - [...]

 New build ordner:

  Main Makefile:

      - [...]
      - nxcomp
      - setup nx-X11 build env
        + cd nx-X11 && make BuildEnv
      - nxcompext
      - nxcompshad
      - nx-X11/lib/*
      - [...]
      - nxagent
      - [...]

 Fixes ArcticaProject/nx-libs#141
 Fixes X2GoBTS#84

 The x2goagent package is being replaced by an x2goserver bin:package
 named x2goserver-x2goagent.

 This x2goserver-x2goagent bin:package will be maintained in the X2Go
 Project's namespace and basically wraps around nxagent.

 Furthermore, declare Arctica Project as upstream source for nx-libs.

X2Go Agent: Add x2goagent.features file that informs X2Go clients about the new RandR based Xinerama feature.

library clean-up: Don't build libNX_Xinerama anymore. Use system's libXinerama shared library. (Fixes ArcticaProject/nx-libs#49).

 This commit goes along with a patch from Ulrich Sibiller who managed to
 move the Xinerama awareness for NX sessions into the Xserver code. This
 makes Xinerama support for NX in libNX_Xinerama.so obsolete.

 Fixes ArcticaProject/nx-libs#49