As discussed in ArcticaProject/nx-libs#610, we need a way to load
libNX_X11 as a fake version of libX11 into nxagent's address space.

For doing so, we have to link against libX11 at build-time and specify
a(n) RPATH/RUNPATH to our libX11 -> libNX_X11 compat symlinks.

This commit is essentially doing a cross between options 3 and 4
discussed in the provided GH issue.

We link libX11 early (before specifying -Lcompat_symlinks_dir), so that
the linker finds the "real" libX11 version with the libX11 SONAME. This
leads to our binary depending upon both libX11 and libNX_X11 SONAMEs. We
already always added RPATH/RUNPATH, but these values are not passed down
to dependent libraries.

What happens at run-time is that the loader searches for a libX11
SONAME, takes RPATH/RUNPATH into account and loads our libNX_X11 library
instead via the compat symlinks. This satisfies the libX11 SONAME and
dependent libraries will *not* load the system libX11 version again.

Debian's dpkg-shlibdeps isn't quite happy about this mismatching SONAME
situation, so instruct to look the other way while we're minding our
business.

Fixes: ArcticaProject/nx-libs#610

debian/control: All Priority: extras packages are required to be changed to Priority: optional by recent Debian Policy.

The initial problem that required this workaround has been fixed a long
time ago.

 Fixes ArcticaProject/nx-libs#546.

Mid-release fixup: split up debian/patches/1500_all_propagate-optflags-to-subcompone.full+lite.patch.

Put server changes into
debian/patches/1500_all_propagate-optflags-to-subcompone.full.patch
and keep client changes local to
debian/patches/1510_all_propagate-optflags-to-subcompone.full+lite.patch.

Mid-release fixup: rename debian/patches/1400_nx-X11_Render.c-Improve-situation-fo.full+lite.patch to debian/patches/1400_nx-X11_Render.c-Improve-situation-fo.full.patch.

Fixes: ArcticaProject/nx-libs#536

Allowing overrides via NX_TEMP and TEMP breaks system using
pam_tmpdir.so and most server infrastructure expects the location to be
fixed anyway.

Backported from Arctica GH 3.6.x branch.

v2: backport to nx-libs 3.5.0.x (Mihai Moldovan)

Adds:
  - debian/patches/1610_nxcomp-harcode-some-UNIX-socket-path.full+lite.patch

Backported from Arctica GH 3.6.x branch.

v2: backport to nx-libs 3.5.0.x (Mihai Moldovan)

Adds:
  - debian/patches/1600_nxcomp-handle-launchd-socket-in-Auth.full+lite.patch

Needed for x2goagent.options file move.

debian/control: change Breaks statement to pre-4.0.1.21 x2goserver and add a Replaces: x2goserver << 4.0.1.21 section to x2goagent package.

We'll do the /etc/x2go/x2goagent.options file move for x2goserver
4.0.1.21 and nx-libs 3.5.0.33 already.

Backported from Arctica GH 3.6.x branch.

v2: backport to nx-libs 3.5.0.x (Mihai Moldovan)

Adds:
  - debian/patches/1500_all_propagate-optflags-to-subcompone.full+lite.patch

Hopefully just a temporary workaround until
https://bugzilla.redhat.com/show_bug.cgi?id=1489712 /
https://bugs.centos.org/view.php?id=13779 are resolved.

Backported from Arctica GH 3.6.x branch.

v2: backport to nx-libs 3.5.0.x (Mihai Moldovan)

nxcomp: Reduce control->TokenSize slightly again in order to fix fragmentation of packages when on VPN (or otherwise encapsulated) connections.

Backported from Arctica GH 3.6.x branch.

v2: backport to nx-libs 3.5.0.x (Mihai Moldovan)

Adds:
  - debian/patches/1301_nxcomp_Reduce-TokenSize-slightly-for.full+lite.patch