First we check to see if we are on the iOS or tvOS. If not, then we defer back to OS X.
TARGET_OS_IPHONE is a variant of TARGET_OS_MAC, which makes this whole thing really stupid.
Mapping generic classes like PINImage, PINImageView and PINButton to the equivalent UIKit or AppKit classes. Throughout the framework use these mappings instead of the concrete UIKit / AppKit names. Furthermore we provide a category on NSImage that is adding methods that are not available on NSImage but on UIImage.
