APPLE MACH-O LINKED ERROR After adding AFNetworking
I had a very similar issue and was seeing about 15 mach -0 linker compiler error messages. Adding the security framework reduced that # to 7 errors.
Did some more research and found that you might also need to add the SystemConfiguration.framework via xCode.
This completely resolved the issue for me.
As an FYI - I was using xCode 5, targeting iOS 7 and using AFNetworking version 2.0.
Adding as an answer, in case other people find that simply adding security.framework doesnt resolve things for them.
Thanks to Cody above for the accepted answer.