Mac: Tool window regression

In 4.x it was possible to have a Qt::Tool window without title bar, by specifying Qt::Tool | Qt::CustomizeWindowHint or Qt::Tool| Qt::FramelessWindowHint.
This is not possible anymore (while it is on Windows). As an example, this breaks the Qt example:
qtbase\examples\widgets\mainwindows\mainwindow\mainwindow.pro
if you run this example and make floating the window with a custom titme bar, you will see the standard Mac window on top, which is wrong. This was not so in 4.8.

I propose the following fix that works for me:
in file qtbase\src\plugins\platforms\cocoa\qcocoawindow.mm
in API QCocoaWindow::windowStyleMask

Replace

        if (!windowIsPopupType(type))
		styleMask = (NSUtilityWindowMask | NSResizableWindowMask | NSClosableWindowMask |
                         NSMiniaturizableWindowMask | NSTitledWindowMask);

with

        if (!windowIsPopupType(type))
		if (flags & Qt::FramelessWindowHint)
			styleMask = NSUtilityWindowMask;
		else
			styleMask = (NSUtilityWindowMask | NSResizableWindowMask | NSClosableWindowMask |
                         NSMiniaturizableWindowMask | NSTitledWindowMask);