QTimeZone - Fix Mac Transistions

Fix nextTransitions() where there are no next transitions and improve
performance of previousTransition() and data().

Change-Id: I5d44525554243d139ba8d5f86e41bdfc0f7bfc25
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
QTimeZone - Fix Windows Transitions

The Windows tz transition routines were not checking for a number of
invalid scenarios, in particular where there are no next transitions
able to be calcualted, leading to infinite loops.

Change-Id: I262b4321a95be1df4228774ada3908f8d3ed6c1a
Reviewed-by: Mitch Curtis <mitch.curtis@digia.com>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Avoid signed integer overflow by making an addition a subtraction

The task has a very good explanation. The use-case was
  ba.remove(n, INT_MAX);
since you can't pass -1 to the length, and that results in overflow when
you add n+INT_MAX.

Task-number: QTBUG-34694
Change-Id: I365eb86b2d0dabbe0bde67e4e7f33d64fd5793af
Reviewed-by: Olivier Goffart <ogoffart@woboq.com>
Android native message dialog

Change-Id: Ief8c3ce3b8683c6960f046245844c1835a327d51
Reviewed-by: Shawn Rutledge <shawn.rutledge@digia.com>
Document the BC break of viewportSizeHint() in itemviews

Since users were not supposed to use this feature at all, just
live with the BC break, but document it. In order to prevent possible
problems in the future, introduce dummy overrides in QAbstractItemView
and QListView as well. Also, fix the visibility of the overrides
(it's protected, not public).

Task-number: QTBUG-34667
Change-Id: Ib4554ae5e1e7d3ce4ea8e8703e1fea9e2231edb0
Reviewed-by: Marc Mutz <marc.mutz@kdab.com>