我在我现有的Google Maps SDK xcode项目中整合了webrtc。它需要添加-ObjC链接器标志，因此我得到了很多重复错误：
duplicate symbol _OBJC_CLASS_$_ARDAppClient in:
/Users/phuongle/Library/Developer/Xcode/DerivedData/Build/Intermediates/AppRTCDemo.build/Debug-iphoneos/AppRTCDemo.build/Objects-normal/armv7/ARDAppClient.o
AppRTCDemo/WebRTC/libWebRTC-armv7.a(apprtc_signaling.ARDAppClient.o)
...
duplicate symbol _OBJC_CLASS_$_ARDAppEngineClient in:
/Users/phuongle/Library/Developer/Xcode/DerivedData/Build/Intermediates/AppRTCDemo.build/Debug-iphoneos/AppRTCDemo.build/Objects-normal/armv7/ARDAppEngineClient.o
AppRTCDemo/WebRTC/libWebRTC-armv7.a(apprtc_signaling.ARDAppEngineClient.o)
...
duplicate symbol _OBJC_CLASS_$_ARDCEODTURNClient in:
/Users/phuongle/Library/Developer/Xcode/DerivedData/Build/Intermediates/AppRTCDemo.build/Debug-iphoneos/AppRTCDemo.build/Objects-normal/armv7/ARDCEODTURNClient.o
AppRTCDemo/WebRTC/libWebRTC-armv7.a(apprtc_signaling.ARDCEODTURNClient.o)
...
duplicate symbol _SRWebSocketErrorDomain in:
/Users/phuongle/Library/Developer/Xcode/DerivedData/Build/Intermediates/AppRTCDemo.build/Debug-iphoneos/AppRTCDemo.build/Objects-normal/armv7/SRWebSocket.o
AppRTCDemo/WebRTC/libWebRTC-armv7.a(socketrocket.SRWebSocket.o)
ld: 114 duplicate symbols for architecture armv7
clang: error: linker command failed with exit code 1 (use -v to see invocation)
如果我删除-ObjC链接器标志，我可以无错误地构建。非常感谢你的建议