将以下命令中 Xcode9xxxx.app 改成你Xcode9的自定义名字

真机

sudo cp /Applications/Xcode9xxxx.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS.sdk/usr/lib/libstdc++.6.0.9.tbd /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS.sdk/usr/lib/libstdc++.6.0.9.tbd

模拟器

sudo cp /Applications/Xcode9xxxx.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator.sdk/usr/lib/libstdc++.* /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator.sdk/usr/lib/

替换完成后在模拟器iOS10.0以上运行会出现一个错误：

Reason: no suitable image found.  Did find:

    /usr/lib/libstdc++.6.dylib: mach-o, butnotbuiltforiOS simulator

sudo cp /Applications/Xcode9xxxx.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/Library/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/usr/lib/libstdc++.6.0.9.dylib /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/Library/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/usr/lib

拷贝进去之后将名字改成libstdc++.6.dylib