This reverts commit ac0184d608. That
commit added the use of qHash in qt_safe_ftok, which made ftok even more
unsafe than previously. Since the algorithm in qHash can change across
Qt versions, we need a stable algorithm instead.
[ChangeLog][Important Behavior Changes] Reverted a change that caused Qt
5.6 through 5.8 not to connect to QSystemSemaphore and QSharedMemory
created by running applications using Qt earlier than
5.6. Unfortunately, this means that Qt 5.9 will not connect to 5.6-5.8.
Task-number: QTBUG-60771
Change-Id: Ibc3472e1c11d46358357fffd14bf51aeb48ef2c8
Reviewed-by: Lars Knoll <lars.knoll@qt.io>