我在 iMac（2010 年初）上使用 Ruby 时遇到了问题。我安装了 Mac OS X Yosemite 预览版，但这些问题一直困扰着我，所以我无法想象 OS X 是这里的错误原因。
每当我尝试 ruby 命令、gem 或应用程序（例如 Cocoapods）时，都会出现以下错误：
/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:55:in `require': cannot load such file -- xcodeproj/prebuilt/universal.x86_64-darwin14-2.0.0/xcodeproj_ext (LoadError)
from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:55:in `require'
from /Library/Ruby/Gems/2.0.0/gems/xcodeproj-0.17.0/lib/xcodeproj/ext.rb:6:in `rescue in <top (required)>'
from /Library/Ruby/Gems/2.0.0/gems/xcodeproj-0.17.0/lib/xcodeproj/ext.rb:3:in `<top (required)>'
from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:55:in `require'
from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:55:in `require'
from /Library/Ruby/Gems/2.0.0/gems/xcodeproj-0.17.0/lib/xcodeproj.rb:30:in `<top (required)>'
from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:55:in `require'
from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:55:in `require'
from /Library/Ruby/Gems/2.0.0/gems/cocoapods-0.33.1/lib/cocoapods.rb:2:in `<top (required)>'
from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:55:in `require'
from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:55:in `require'
from /Library/Ruby/Gems/2.0.0/gems/cocoapods-0.33.1/bin/pod:32:in `<top (required)>'
from /usr/bin/pod:23:in `load'
from /usr/bin/pod:23:in `<main>'
我发现的所有重新安装 Ruby、RVM 等的指南和教程都没有用。有什么想法吗？