1. 当我pod init 的时候 提示如下：
Ignoring ffi-1.15.5 because its extensions are not built. Try: gem pristine ffi --version 1.15.5
解决：sudo gem install ffi -v 1.15.5
参考链接：https://www.jianshu.com/p/f91e0b388e6b
2. Automatically assigning platform `iOS` with version `16.2` on target `TestPod` because no platform was specified. Please specify a platform for this target in your Podfile. See `https://guides.cocoapods.org/syntax/podfile.html#platform`.
参考链接：https://blog.csdn.net/jdd92/article/details/127446216
3. 解决完上面两个问题后，再次执行pod init ， 还是不行，具体提示什么问题，忘记了，我就参考了：https://www.jianshu.com/p/7c188ab7ccb6里的安装Cocopods的步骤sudo gem install -n /usr/local/bin cocoapods 就可以了
