I'm attempting to build rubygems on AIX.  It's failing with:

/afs/austin/u/mattlaw/ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:21:in 
`require__': No such file to load -- zlib (LoadError)
         from 
/afs/austin/u/mattlaw/ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:21:in 
`require'
         from 
/afs/austin/u/mattlaw/ruby/lib/ruby/site_ruby/1.8/rubygems/package.rb:9
         from 
/afs/austin/u/mattlaw/ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:21:in 
`require__'
         from 
/afs/austin/u/mattlaw/ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:21:in 
`require'
         from 
/afs/austin/u/mattlaw/ruby/lib/ruby/site_ruby/1.8/rubygems/builder.rb:1
         from 
/afs/austin/u/mattlaw/ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:21:in 
`require__'
         from 
/afs/austin/u/mattlaw/ruby/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:21:in 
`require'
         from 
/afs/austin/u/mattlaw/ruby/lib/ruby/site_ruby/1.8/rubygems.rb:61:in 
`manage_gems'
          ... 7 levels...
         from setup.rb:887:in `exec_install'
         from setup.rb:705:in `invoke'
         from setup.rb:674:in `invoke'
         from setup.rb:1352

Help?

-- Matt
Nothing great was ever accomplished without _passion_