将 swift 从 3.2 版更新到 4.0 版后，Carthage 构建失败。以下是使用carthage update --platform iOS.
*** Fetching AlamofireImage
*** Fetching FSCalendar
*** Fetching Alamofire
*** Fetching ActiveLabel.swift
*** Fetching Toaster
*** Fetching PopupDialog
*** Fetching DKImagePickerController
*** Checking out DKImagePickerController at "3.6.1"
*** Checking out PopupDialog at "0.5.4"
*** Checking out Toaster at "2.1.0"
*** Checking out ActiveLabel.swift at "0.8.0"
*** Checking out Alamofire at "4.5.1"
*** Checking out FSCalendar at "2.7.9"
*** Checking out AlamofireImage at "3.3.0"
*** xcodebuild output can …