Gem Install memcached-northscale error

Trying to install memcached-northscale and getting a weird error. Any help would be appreciated.

$ sudo gem install memcached-northscale
Building native extensions.  This could take a while...
ERROR:  Error installing memcached-northscale:
ERROR: Failed to build gem native exte开发者_StackOverflownsion.

/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/bin/ruby extconf.rb
mkmf.rb can't find header files for ruby at /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/ruby.h

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I was able to fix the issue by installing XCode from Apple