Xcode 7 error : undefined symbols for arm64

[gunshi]

Hi, i recently was able to compile the project successfully on Xcode 6, then i upgraded to Xcode 7 which now also builds for arm64 apart from armv6 and armv7, and it gives me several errors such as these:
Undefined symbols for architecture arm64:
"cv::CascadeClassifier::CascadeClassifier() .....
I just wanted to ask if this is because of an issue with the opencv.framework file, and it being not built for arm64.(i do want to support arm64, should i build opencv for iOS from source myself?)
Any help would be greatly appreciated.
Thanks!