This is needed to support passing it to other processes so they can
enable legacy, compatibility mode. Right now, there's no such code, but
I am 90% certain we'll need it soon in 6.6.x, if not for compatibility
changes in the future.
There's a bug in passing a QNativeIpcKey to another process that causes
QSharedMemory to use the wrong QSystemSemaphore for control (a feature
that should never have existed in the first place, but we're 15 years
too late on that). I have not yet investigated a fix for this, but it
will likely involve knowing the original legacy key.
Pick-to: 6.6 6.6.0
Change-Id: Idd5e1bb52be047d7b4fffffd1750b547013cb336
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>
9edb835904