To work with Xcode 7 and Swift 2 supported frameworks, before carthage * run xcode-select #536
Description
sudo xcode-select -s /Applications/Xcode-beta.app/Contents/Developer
By running this command, you set the default xcodebuild to the one in Xcode 7 beta.
Hope this helps people who get errors when updating to Swift 2 supported frameworks, for example github "Quick/Quick" "swift-2.0" as in Cartfile.