I am getting a Apple Mach-O Linker Error everytime I import a file from CocoaPods.
Undefined symbols for architecture arm64:
\"_OBJC_CLASS_$_FBSession\", r
For me, I use opencv 2.4.9 in xcode 7.2 for iOS and the errors above occurred, and I solve the errors by using the opencv through pod install rather than offline opencv framework.
You can have a try by adding the opencv pod text below and delete the offline opencv framework if you have used.
pod 'OpenCV', '2.4.9'