clear OBJECTIVE_SOURCES as well

the newly added mac examples use it, so it needs to be grounded.

a more generic solution would be clearing out QMAKE_EXTRA_COMPILERS, but
many prf files will be loaded after us, possibly nullifying our effort.

Task-number: QTBUG-35680
Change-Id: I3aba7595898baac14bd41e9fae2ff24507187c6a
Reviewed-by: Joerg Bornemann <joerg.bornemann@digia.com>
Fix warning in QVariant test.

Values from different enums were compared.

Change-Id: I2faf73976e4b24abbdc915e8445256fe7a5be5bd
Reviewed-by: Stephen Kelly <stephen.kelly@kdab.com>
Reviewed-by: Jędrzej Nowacki <jedrzej.nowacki@digia.com>
Mac: Improve transformed QGraphicsProxyWidgets

Restore Mac code paths from Qt 4.

Task-number: QTBUG-29139
Change-Id: I2893ddf6015e2bda92d4a16980dbe2c9021eeef7
Reviewed-by: Morten Johan Sørvig <morten.sorvig@digia.com>