In MacOSX 10.6 and above the NSOpenPanel beginSheetForDirectory
method is deprecated. Use the preferred replacements instead.
We retain the original code for use on earlier MacOSX versions
because the replacement methods don't exist before 10.6.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Andreas Färber <andreas.faerber@web.de>