debian/rules: Don't use -pie -fPIE at build time for 3.5.99.2 as it causes nxagent to segfault. Investigating the reasons behind it is in process...

debian/rules: Don't modify/create post{inst,rm} scripts during dh_makeshlibs. This avoids adding ldconfig calls to such scripts.

debian/nxproxy.docs: Fix FTBFS due to missing documentation files (moved out of the way with recent commits).

debian/control: Add some hard and exact-versioned dependencies for our bin:packages. Assure that no old share lib packages with the same set of symbols remain on the system when upgrading.

  - 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
    ```

use system libXext instead

debian/*.dirs: Don't create directories in the Debian package. All handled well by the upstream Makefile.

debian/control: Drop various not-used-anymore libNX_* related packages. Add B:/R: to libnx-x11-{6,dev,6-dbg) to uninstall those package when upgrading to nx-libs 3.6.x.

roll-tarball.sh: Don't ship doc/X11-symbols/ in the lite (proxy-only) tarball derived from the nx-libs code tree.

debian/rules: Don't attempt at removing $(CURDIR)/.preserve/. Not needed anymore since we removed the CODE-REDUCTION_* hacks from debian/rules.

 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