no such file to load — mkmf

Today I was attempting to install a package on my ubuntu machine and I received the following error:

extconf.rb:1in 'require': no such file to load -- mkmf (LoadError)

To solve the problem, I simply installed the ruby1.8-dev package, this was done by the command:

sudo apt-get install ruby1.8-dev

I could then happily install the package I wanted.