When creating a static library that I write using the iOS 8 SDK, the resulting library is linked to a metal frame:
$ otool -arch all -fl <static library>
...
Load command 12
519 cmd LC_LINKER_OPTION
520 cmdsize 32
521 count 2
522 string #1 -framework
523 string #2 Metal
...
I think this happens through UIKit; I do not contact him directly, and the "Link to standard libraries" is NOT. This causes problems with Xcode 5.1.1 with iOS 7 because this environment does not exist. Building a static lib with Xcode 5 is not metal-related, but I would rather build with the latest release of Xcode, and at some point I will have to solve this problem. How can I build with Xcode 6 and work around this problem for Xcode 5 users?
. , , , Metal, , UIKit:
https://github.com/card-io/card.io-iOS-SDK/issues/66
https://github.com/CocoaPods/CocoaPods/issues/2457