On macOS 10.15 and newer, trying to open the device node of a removable
drive will trigger an "<app> would like to access files on a removable
volume" permission prompt, even if the user doesn't have permissions
to access the device node (which is almost always the case).

Check the value of access() (recommended by Apple for this purpose)
before opening devices.
Signed-off-by: Brendan Shanks <bshanks@codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>