Fix logic for figuring out what ConfigureNotify positions can be trusted

When reading ahead in the queue for ConfigureNotify events, it's necessary
to look for intermediate ReparentNotify events as well, since they will
determine whether the position in the event can be trusted or not.

Bug: https://bugreports.qt.nokia.com/browse/QTBUG-21900

Gbp-Pq: Name QTBUG-21900_Buttons_in_Qt_applications_not_clickable_when_run_under_gnome-shell.patch

Add_support_for_QT_USE_DRAG_DISTANCE_env_var

from QT_USE_DRAG_DISTANCE environment variable.
See also http://bugreports.qt.nokia.com/browse/QTBUG-12594
Author: Joonas Tanskanen <joonas.tanskanen@sasken.com>

Gbp-Pq: Name Add_support_for_QT_USE_DRAG_DISTANCE_env_var.patch

qt4-x11 (4:4.8.7+dfsg-17+rpi2) buster-staging; urgency=medium

  * Replace a number of occourances of "asm" with "__asm"

[dgit import unpatched qt4-x11 4:4.8.7+dfsg-17+rpi2]

Import qt4-x11_4.8.7+dfsg-17+rpi2.debian.tar.xz

[dgit import tarball qt4-x11 4:4.8.7+dfsg-17+rpi2 qt4-x11_4.8.7+dfsg-17+rpi2.debian.tar.xz]

Import qt4-x11_4.8.7+dfsg.orig.tar.xz

[dgit import orig qt4-x11_4.8.7+dfsg.orig.tar.xz]