Could not build module UIKit
A full clean + deleting the derived data worked for me.
Be sure to fix any code that may be broken because UIKit cannot be installed, before the clean and build.
So, for example, if you are trying to reference UICollectionViewController, and need UIKit to reference it, comment out the code that is using UICollectionViewController, comment out the import for UIKit.
Then clean, build. Now uncomment import UIKIt, build. NOW uncomment UICollectionViewController code, build again.
