CMP0020
-------

Automatically link Qt executables to ``qtmain`` target on Windows.

CMake 2.8.10 and lower required users of Qt to always specify a link
dependency to the ``qtmain.lib`` static library manually on Windows.
CMake 2.8.11 gained the ability to evaluate generator expressions
while determining the link dependencies from ``IMPORTED`` targets.  This
allows CMake itself to automatically link executables which link to Qt
to the ``qtmain.lib`` library when using ``IMPORTED`` Qt targets.  For
applications already linking to ``qtmain.lib``, this should have little
impact.  For applications which supply their own alternative WinMain
implementation and for applications which use the QAxServer library,
this automatic linking will need to be disabled as per the
documentation.

The ``OLD`` behavior for this policy is not to link executables to
``qtmain.lib`` automatically when they link to the QtCore ``IMPORTED`` target.
The ``NEW`` behavior for this policy is to link executables to ``qtmain.lib``
automatically when they link to QtCore ``IMPORTED`` target.

This policy was introduced in CMake version 2.8.11.  CMake version
|release| warns when the policy is not set and uses ``OLD`` behavior.  Use
the :command:`cmake_policy` command to set it to ``OLD`` or ``NEW`` explicitly.

.. include:: DEPRECATED.txt