Use Q_OS_MAC, not Q_WS_MAC
Use Q_OS_MAC, not Q_WS_MAC

The latter doesn't exist any more in Qt 5.

Change-Id: Ib8430549e8a975626ebfe0cd4ca7c3f6eade1e4f
Reviewed-by: Gabriel de Dietrich <57b5c683f0b6abfc17ef151d5b68c8944258b63a@digia.com>

kobolabs/qtdoc,kobolabs/qtdoc,kobolabs/qtdoc,kobolabs/qtdoc