Heroku Install Troubleshooting on Mac OS 10.6.6

This MBP is brand new. I installed Rails, and it went swimmingly. Now Heroku is giving me this error on install:

MacBook-Pro:~ caselas$ sudo gem install heroku Password: Building native extensions. This could take a while... ERROR: Error installing heroku: ERROR: Failed to build gem native extension.

    /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

Gem files will remain installed in /Library/Ruby/Gems/1.8/gems/json-1.4.6 for inspection. Results logged to /Library/Ruby/Gems/1.8/gems/json-1.4.6/ext/json/ext/generator/gem_make.out

Here is this, to help diagnos:

MacBook-Pro:~ caselas$ gem environment RubyGems Environment: - RUBYGEMS VERSION: 1.5.0 - RUBY VERSION: 1.8.7 (2009-06-12 patchlevel 174) [universal-darwin10.0] - INSTALLATION DIRECTORY: /Library/Ruby/Gems/1.8 - RUBY EXECUTABLE: /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/bin/ruby - EXECUTABLE DIRECTORY: /usr/bin - RUBYGEMS PLATFORMS: - ruby - universal-darwin-10 - GEM PATHS: - /Library/Ruby/Gems/1.8 - /Users/caselas/.gem/ruby/1.8 - /System/Library/Frameworks/Ruby.framework/Versio开发者_运维问答ns/1.8/usr/lib/ruby/gems/1.8 - GEM CONFIGURATION: - :update_sources => true - :verbose => true - :benchmark => false - :backtrace => false - :bulk_threshold => 1000 - REMOTE SOURCES: - http://rubygems.org/

Any ideas?

have you installed Xcode and the 'Unix Development' option during the install?

John.