升级Xcode后, 项目编译时会报错 原因是: 苹果早在 Xcode 8中 就废弃了libstdc++, 真机路径:/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS.sdk/usr/lib/ 模拟器路径:/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator.sdk/usr/lib/