Backported from X.org:

 commit 0df871cf34ee5f1a85586206027de9b02fb364ec
 Author: Robert Ancell <robert.ancell@canonical.com>
 Date:   Thu May 22 10:43:52 2014 +1200

    Fix overflow checking extension versions

    The easiest way to check for the version of an extension is to send the maximum
    possible version numbers in the QueryVersion request. The X server overflows on
    these as it assumes you will send a reasonable version number.
Reviewed-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Keith Packard <keithp@keithp.com>

 commit ffd4874798ba54f86acac75779a15b4babeaa5f3
 Author: Peter Hutterer <peter.hutterer@who-t.net>
 Date:   Wed May 11 12:20:50 2011 +1000

    include: add version_compare helper function

    Compare two version numbers in the major.minor form.
    Switch the few users of manual version switching over to the new function.
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Reviewed-by: Jamey Sharp <jamey@minilop.net>

 Backport to nx-libs: Mike Gabriel <mike.gabriel@das-netzwerkteam.de>