openStandardStreamsFileDescriptors and openStandardStreamsBufferedStreams
fail on OS X: lseek somehow works on sequential streams (standard streams)
but QFile has pos() == 0 (since it's sequential).
Change-Id: I6a6161c012a91de189f59c533880fb8fe7a66d37
Task-number: QTBUG-49841
Reviewed-by: Morten Johan Sørvig <morten.sorvig@theqtcompany.com>
Reviewed-by: Tony Sarajärvi <tony.sarajarvi@theqtcompany.com>