Xcode12 问题
objc_msgSend运行时方法报错，提示No matching function for call to 'objc_msgSend',google 了下,有人反馈是Xcode12的bug。Enable Strict Checking of objc_msgSend Calls 配置设为NO 无效。
xcversion 安装多版本Xcode
gem install xcode-install
xcversion list
xcversion install 11.3
xcversion select --symlink 11.3
xcversion uninstall 10.3
安装Xode10 或 11以后 报错 library not found for -libstdc++.6.0.9
将仓库里的文件放在下面目录即可
1.真机环境：/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS.sdk/usr/lib/
2.模拟器环境：/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator.sdk/usr/lib/
