mac 下 gem安装 compass 遇到 '-multiply_defineds'

curl https://gist.githubusercontent.com/Paulche/9713531/raw/1e57fbb440d36ca5607d1739cc6151f373b234b6/gistfile1.txt | sudo patch /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/universal-darwin13/rbconfig.rb

只须要在命令行上 执行这句就能够了。（我亲测能够  mac 10.9）

原文地址：http://stackoverflow.com/questions/22352838/ruby-gem-install-json-fails-on-mavericks-and-xcode-5-1-unknown-argument-mul