Fixes ArcticaProject/nx-libs#63

Xinerama symlinking: Create / remove folder containing Xinerama sylinks on installation/upgrade and removal.

Various fixes for pkgconfig file creation.

This reverts commit b77b26f4.

Should be a weak dependency, but RPM doesn't support that too well yet.

Cherry-picked from 3.5.0.x branch.

Cherry-picked from 3.5.0.x branch.

 As the system a tarball gets extracted on may potentially be unable
 to handle symlinks, we ship symlinks as files in the rolled tarball.

 By transforming symlinks into real files, we also assure that all
 VERSION files/symlinks get shipped in the tarballs.

 Fixes ArcticaProject/nx-libs#27

debian/libxcomp{,ext,shad}-dev.install.in: Install nxcomp{,ext,shad}.pc file into the corresponding development packages.

xorg-server does not follow the convention of using 2 dashes,
and apparently nx-libs doesn't either.

Note that --help does produce the help output. However, it
produces this additional output after it:

Error: NX transport initialization failed.

Therefore, we should instruct users to call -help instead.

xorg-server does not follow the convention of using 2 dashes.

Note that --help does produce the help output. However, it
produces this additional output after it:

Error: Aborting session with 'Unrecognized option: --help'.
Session: Aborting session at 'Sun Jun 28 01:35:35 2015'.
Session: Session aborted at 'Sun Jun 28 01:35:35 2015'.

It also causes a return code of 1 rather than 0.

Therefore, we should instruct users to call -help instead.

COPYING: Replace content with GPL-2 license text, because that is the overall (i.e., strictest) license we have to deal with in nx-libs.

debian/roll-tarball.sh: Rename README.md to README.NX-Development before moving it into doc/ folder.

* bin/{nxagent,nxauth,x2goagent}
* etc/
* doc/nx-X11_vs_XOrg69_patches
* README.keystrokes"
* nx-libs.spec

debian/roll-tarball.sh: Allow patch files names having a dash next to the four digits (i.e., 1234-<patchname>.<suffix>).

 Due to C arithmetic conversion rules we must use an unsigned constant (or a
 cast) to perform the multiplication using unsigned arithmetic.

 Fixes ArcticaProject/nx-libs#55.

 Author: Emanuele Giaquinta <emanuele.giaquinta@gmail.com>
Reviewed-by: Jeremy Huddleston <jeremyhu@apple.com>
 Rebased against NX: Mike Gabriel <mike.gabriel@das-netzwerkteam.de>