Mac: Changes for supporting Big Sur. These changes don't actually work. The Xcode beta SDK is listed as 10.16, although it has been reported that Big Sur will be 11.0 not 10.16. The 10.16 SDK does not include constants for either 10.16 or 11.0 so I am writing the code as if it will be 11.0. The 10.16 SDK complains that NSBox's setBorderType is deprecated and it seems like the styles don't apply to the box type I am using anyway, so might want to just remove the setBorderType from NSBox and see if it still works on other versions of MacOS, but committing for now so I have this record of it.

# Set these here to change the version for all platforms
DW_MAJOR_VERSION=3
DW_MINOR_VERSION=1