nxcomp{,shad}/configure.ac: replace versionating non-portable sed construct with hopefully more portable awk construct.

Keeping it enabled leads to nxagent consuming 100% of CPU resources
after some time.

Older code used three different timers for each DPMS mode (standby,
suspend, off), with each timer checking that the elapsed idle time is
strictly less than the DPMS mode timeout value.

Newer code started merging DPMS and ScreenSaver timers into a single
one, with checking DPMS modes and timeouts in a fall-through fashion.
The code expects that, if a timeout is reached, the mode is set
accordingly, so that the old timeout is disregarded next time.

Since we stub out DPMSSetMode() in nxagent, this doesn't happen.

In this case, the old DPMS timeout will be checked the next time around
and we will be calculating DPMS_MODE_TIMEOUT - IDLE_TIME. If IDLE_TIME
is bigger than DPMS_MODE_TIMEOUT, we run into problems with unsigned
integers. What happens next will be *another* overflow once DoTimers()
is executed and from that function SetTimers(), which will add the
current timestamp to the timeout value. Later functions subtract the
current timestamp again (which will be even higher since some time
elapsed) and underflow the value again.

It looks like this leads to consistent firing of the timer - something
we do not want to have.

For new, disable DPMS support in nxagent. We do not execute it on actual
hardware that could change DPMS modes.

At a later time, implementing a DPMS timeout/mode passthrough to the
connected X server/display might be beneficial.

Fixes: ArcticaProject/nx-libs#671

Attributes GH PR #624: https://github.com/ArcticaProject/nx-libs/pull/624

hw/nxagent/Screen.c: Settle down with 96 DPI as the default resolution, if nothing better can be detected.

Fixes ArcticaProject/nx-libs#668.

Attributes GH PR #667: https://github.com/ArcticaProject/nx-libs/pull/667

is used nowhere anyway

make them appear in the nx section. Also separate the nx section from the
other options by an extra emtpy line.

Attributes GH PR #648: https://github.com/ArcticaProject/nx-libs/pull/648

In XORG-7_1 xkbconfig.c had been dropped. We must keep this file
because it is used by hw/nxagent/Keyboard.c to load the xkb
configuration file. Maybe we should move the relevant code to there or
drop xkb configuration file support from nxagent.

Revert "nx-libs.spec: Starting with Fedora 28 / RHEL 8, SunRPC support is being split out into a separate libraries (libtirpc)."

This reverts commit 9f93e96e.

nx-libs.spec: Starting with Fedora 28 / RHEL 8, SunRPC support is being split out into a separate libraries (libtirpc).

Fixes ArcticaProject/nx-libs#665.

Attributes GH PR #522: https://github.com/ArcticaProject/nx-libs/pull/522

nxagent: Also provide auto DPI feature via nx/nx option 'autodpi', taking only effect on session startups.

Fixes ArcticaProject/nx-libs#617.

{nx-X11/programs/Xserver/hw/nxagent/man/nxagent.1,nxproxy/man/nxproxy.1}: magicpixel takes a boolean argument for now.

Fixes: ArcticaProject/nx-libs#664

nxcomp/src/Loop.cpp: Make know the agent option 'keyconv' to nxcomp and tolerate it as a valid option.

Fixes ArcticaProject/nx-libs#630.

Attributes GH PR #651: https://github.com/ArcticaProject/nx-libs/pull/651

Backported from X.org:

commit 39ce5f1544029412f4060f3e89ce1d87222ef42b
Author: Adam Jackson <ajax@nwnk.net>
Date:   Fri Jan 6 17:05:26 2006 +0000

    Remove unused X11R4 DDX compatibility function miClipNotify.
Backported-to-NX-by: Mihai Moldovan <ionic@ionic.de>

Attributes GH PR #650: https://github.com/ArcticaProject/nx-libs/pull/650

I left out glx changes to miinitext.c for now.

Attributes GH PR #649: https://github.com/ArcticaProject/nx-libs/pull/649