This resolves issues with non-starting mate-screensaver which
 relies on the IDLETIME API these days.

 This commit backports the following X.org Xserver commits:

    commit a2e67a6412386782cb8b644b86a5744591397d45
    Author: Christopher James Halse Rogers <christopher.halse.rogers@canonical.com>
    Date:   Mon Dec 6 11:24:01 2010 +1100

        IDLETIME: Fix edge-case in IdleTimeBlockHandler

        Ensure that if we're called exactly on the threshold of a
        NegativeTransition trigger that we reshedule to pick up
        an idle time over the threshold.
Signed-off-by: Christopher James Halse Rogers <christopher.halse.rogers@canonical.com>
Reviewed-by: Adam Jackson <ajax@redhat.com>
Signed-off-by: Keith Packard <keithp@keithp.com>

    commit 1f4fb0225b278d1cf4145aebeb0bdd23dc8f62d5
    Author: Adam Jackson <ajax@redhat.com>
    Date:   Wed Dec 10 16:13:20 2008 -0500

        xsync: Fix wakeup storm in idletime counter.

        Wakeup scheduling only considered the threshold values, and not whether
        the trigger was edge or level.

        See also:
        https://bugzilla.redhat.com/show_bug.cgi?id=474586
        http://svn.gnome.org/viewvc/gnome-screensaver/trunk/src/test-idle-ext.c?view=markup

    commit 0f9e89b4e309e570d7d366489d250ca2143f0ad7
    Author: Fredrik Höglund <fredrik@kde.org>
    Date:   Tue Aug 14 22:47:49 2007 +0200

        Fix the value comparisons in the IDLETIME wakeup handler.

        LessThan/GreaterThan comparisons were used in the wakeup handler,
        and LessOrEqual/GreaterOrEqual in the block handler.

        Change it to use LessOrEqual/GreaterOrEqual in both functions,
        since this is what XSyncNegativeComparison and
        XSyncPositiveComparison imply.

    commit 7e2c935920cafadbd87c351f1a3239932864fb90
    Author: Fredrik Höglund <fredrik@kde.org>
    Date:   Fri May 18 20:06:14 2007 +0200

        Add a new IDLETIME system sync counter.

        This counter exposes the time in milliseconds since the last
        input event. Clients such as screen savers and power managers
        can set an alarm on this counter to find out when the idle time
        reaches a certain value, without having to poll the server.
Backport-to-NX-by: Mike Gabriel <mike.gabriel@das-netzwerkteam.de>