cocoapods安装 xcode 12问题

To see why this extension failed to compile, please check the mkmf.log which can be found here:

  /Library/Ruby/Gems/2.6.0/extensions/universal-darwin-19/2.6.0/ffi-1.15.0/mkmf.log

extconf failed, exit code 1

fatal error: 'ruby/config.h' file not found

使用此命令安装 

sudo xcrun gem install cocoapods --source http://rubygems.org