This is just a heads up as it took me ages to figure this out. When using the new build system preview in Xcode 9, there seems to be an error when running the start method in the new TwitterKit SDK, you get the below:
*** Terminating app due to uncaught exception ‘NSInternalInconsistencyException’, reason: ‘TwitterKitResources.bundle resources file not found. Please re-install TwitterKit with CocoaPods to ensure it is properly set-up.’
To fix it you have to clean then rebuild using the standard build system and then it runs ok. I presume this is because the new build system doesn’t pick the bundle up and compile the source.