yasuharu-note:~/development/ruby/sinatra-test:{191}> sudo gem install fcgi
Building native extensions. This could take a while...
ERROR: Error installing fcgi:
ERROR: Failed to build gem native extension.
/usr/bin/ruby1.8 extconf.rb install fcgi
extconf.rb:1:in `require': no such file to load -- mkmf (LoadError)
from extconf.rb:1