I am attempting to install the sqlite3 gem under Solaris and am getting the
following error:

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101 beech# gem install sqlite3-ruby
Building native extensions.  This could take a while...
ERROR:  Error installing sqlite3-ruby:
        ERROR: Failed to build gem native extension.

/opt/csw/bin/ruby extconf.rb install sqlite3-ruby
extconf.rb:1:in `require': no such file to load -- mkmf (LoadError)
        from extconf.rb:1


Gem files will remain installed in /opt/csw/lib/ruby/gems/1.8/gems/sqlite3-ruby-1.2.4 for inspection.
Results logged to /opt/csw/lib/ruby/gems/1.8/gems/sqlite3-ruby-1.2.4/ext/sqlite3_api/gem_make.out
------------------

How do I fix this?

-- 
Will