patch for QTBUG-100059 (namespace issue)

[divideconcept]

Patch as suggested by Michael Spork here: https://bugreports.qt.io/browse/QTBUG-100059
It has been tested successfully on our side.

[torarnv]

https://codereview.qt-project.org/c/qt/qtbase/+/408984

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[DanSoQt]

Already merged, as per Tor Arne.