title: Why am I having a problem installing rmagick
body: <p>On Ruby 1.8.7 and rails 2.3.5 I get:</p>
  
  <pre><code>gem install rmagick
  
  ERROR:  Error installing rmagick:
  
  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/rmagick-2.13.1 for inspection.
  
  Results logged to /Library/Ruby/Gems/1.8/gems/rmagick-2.13.1/ext/RMagick/gem_make.out
  
  Building native extensions.  This could take a while...
  
  Cynicalgrinch:levelous pawel$ gem install rmagick
  
  Building native extensions.  This could take a while...
  
  ERROR:  Error installing rmagick:
  
      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/rmagick-2.13.1 for inspection.
  
  Results logged to /Library/Ruby/Gems/1.8/gems/rmagick-2.13.1/ext/RMagick/gem_make.out
  
  
  Gem_make.out says this:
  
  /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
  </code></pre>