# gem1.8 install postgres
Building native extensions.  This could take a while...
ERROR:  Error installing postgres:
        ERROR: Failed to build gem native extension.

/usr/bin/ruby1.8 extconf.rb
extconf.rb:46:in `require': no such file to load -- mkmf (LoadError)
        from extconf.rb:46


Gem files will remain installed in /var/lib/gems/1.8/gems/postgres-0.7.9.2008.01.28 for inspection.
Results logged to /var/lib/gems/1.8/gems/postgres-0.7.9.2008.01.28/ext/gem_make.out