卸载Xcode

sudo rm -rf /Applications/Xcode.app
sudo rm -rf /Library/Preferences/com.apple.dt.Xcode.plist
rm -rf ~/Library/Preferences/com.apple.dt.Xcode.plist
rm -rf ~/Library/Caches/com.apple.dt.Xcode
rm -rf ~/Library/Application\ Support/Xcode
rm -rf ~/Library/Developer/Xcode
rm -rf ~/Library/Developer/CoreSimulator
rm -rf ~/Library/Developer/XCPGDevices

AppStore直接下载安装

开发者官网(More Downloads for Apple Developers):
https://developer.apple.com/download/more/

libstdc++库问题处理：
https://github.com/devdawei/libstdc-

参考
https://www.cnblogs.com/CoderHong/p/11253646.html