From the comments the workaround is for MinGW
older than v7, now our CI has MinGW v9 trunk,
it should be safe to drop this.
The magic number is replaced by the official function,
although it was introduced in Win8, Qt6's minimum
supported platform is Win10, so it's also safe to do.
As a drive-by, remove two unused includes.
Change-Id: I891fe3883f17d4914932784868d7446299d32c65
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
ae7e11e5c6