NDKr12 LOCAL_SRC_FILES points to a missing file.a in path ../arm64-v8a/file.a

my game is using cocos2dx 2.2.6 I have upgrade the NDK to the the NDKr12 beta1 and try to build my project then I get so many errors at the NdkModule folder and NDK complain that it doesn't found the output file in Ndk Module Path: cocos2dx/platform/third_party/android/prebuilt/lib*/libs/arm64-v8a/file.a what it that mean and how to fix it?

I manage to solve it by specific the target architectures at application.mk by adding this line:

APP_ABI := armeabi armeabi-v7a x86