我的引擎用的是3.2版本的，admob用的是7.9.1，运行报下面的错误，如何解决
Undefined symbols for architecture armv7:
“OBJC_CLASS_CBUUID", referenced from:
objc-class-ref in GoogleMobileAds(flat-armv7)
"_OBJC_CLASS__CBCentralManager”, referenced from:
objc-class-ref in GoogleMobileAds(flat-armv7)
“OBJC_CLASS_SFSafariViewController", referenced from:
objc-class-ref in GoogleMobileAds(flat-armv7)
"_OBJC_CLASS__GLKView”, referenced from:
objc-class-ref in GoogleMobileAds(flat-armv7)
“_kCMTimeZero”, referenced from:
l4053 in GoogleMobileAds(flat-armv7)
“_GLKMatrix4Identity”, referenced from:
l2392 in GoogleMobileAds(flat-armv7)
l2402 in GoogleMobileAds(flat-armv7)
“_CBCentralManagerOptionShowPowerAlertKey”, referenced from:
l942 in GoogleMobileAds(flat-armv7)
“_kCVImageBufferYCbCrMatrix_ITU_R_601_4”, referenced from:
l2397 in GoogleMobileAds(flat-armv7)
“_kCVPixelBufferPixelFormatTypeKey”, referenced from:
l086 in GoogleMobileAds(flat-armv7)
“_CMTimeMakeWithSeconds”, referenced from:
l4055 in GoogleMobileAds(flat-armv7)
“_CMTimeMake”, referenced from:
l4037 in GoogleMobileAds(flat-armv7)
“_CVOpenGLESTextureCacheCreateTextureFromImage”, referenced from:
l2400 in GoogleMobileAds(flat-armv7)
“_CVOpenGLESTextureGetName”, referenced from:
l2400 in GoogleMobileAds(flat-armv7)
“_CVOpenGLESTextureCacheCreate”, referenced from:
l2399 in GoogleMobileAds(flat-armv7)
“_CVPixelBufferGetHeight”, referenced from:
l2397 in GoogleMobileAds(flat-armv7)
“_CVOpenGLESTextureCacheFlush”, referenced from:
l2398 in GoogleMobileAds(flat-armv7)
“_kCVImageBufferYCbCrMatrixKey”, referenced from:
l2397 in GoogleMobileAds(flat-armv7)
“_CVPixelBufferGetWidth”, referenced from:
l2397 in GoogleMobileAds(flat-armv7)
“_CVBufferGetAttachment”, referenced from:
l2397 in GoogleMobileAds(flat-armv7)
“_CMTimeGetSeconds”, referenced from:
l4044 in GoogleMobileAds(flat-armv7)
l4045 in GoogleMobileAds(flat-armv7)
“_CVOpenGLESTextureGetTarget”, referenced from:
l2400 in GoogleMobileAds(flat-armv7)
ld: symbol(s) not found for architecture armv7
clang: error: linker command failed with exit code 1 (use -v to see invocation)
