QDate is a 64bit in Qt 5, which will be aligned on 64bit borders
in 32bit and 64bit builds.
In Qt 4, it will be aligned on 32bit borders for 64bit builds as
well. Differentiate between padded and non-padded types when
retrieving the address of a QSharedData-member.

Change-Id: I6a16d6aa2dc0d5ad85d3d25f71ce09c06bd04c05
Reviewed-by: David Schulz <david.schulz@digia.com>