Installing RCov on Mac OS X.5

I tried installing rcov on my Mac OS 10.5.6

$>sudo gem install rcov
Password:
Building native extensions. This could take a while...
ERROR: Error installing rcov:
ERROR: Failed to build gem native extension.

/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/bin/ruby extconf.rb install rcov
can't find header files for ruby.

Gem files will remain installed in /Library/Ruby/Gems/1.8/gems/rcov-0.8.1.2.0 for inspection.
Results logged to /Library/Ruby/Gems/1.8/gems/rcov-0.8.1.2.0/ext/rcovrt/gem_make.out

Really? That sucks. I asked the interweb and I found this post:
http://www.macruby.org/trac/wiki/Troubleshooting
OK so I installed Xcode 3 from here: http://developer.apple.com/Tools/xcode/ and then installed mac ports from here: http://www.macports.org/

Everything worked after that! Awesome!