Guide was copied from http://stackoverflow.com/a/14353864/1562884 for my reference

Helped me with this error during configuring Octopress on Ubuntu

Error installing RedCloth:
ERROR: Failed to build gem native extension.

Guide below was written by Eric Zhang

My Ubuntu 12.04 solution is install the ruby1.9.1-full version, that can resolve this issue.

$sudo apt-get install ruby1.9.1-full

you can execute command:

$sudo update-alternatives --config ruby

to select the alternative ruby which you have installed. and then, execute below commands to finish the octopress deploy:

$git clone https://github.com/erizhang/octopress.git octopress
$cd octopress/
$sudo gem install bundler
$sudo gem install RedCloth -v '4.2.9'
$bundle install
$rake install

below commands you can find from octopress deploy guideline page:

$rake setup_github_pages
$sudo rake setup_github_pages
$sudo rake generate
$sudo rake deploy

Hope it's helpful for you, thanks