I\'ve been working through the Rails install instructions (http://railsapps.github.io/installrubyonrails-mac.html) and everything was okay up until I got to gem instal
I just had the same problem and was able to solve it as follows:
Installing Nokogiri separately worked only when using the system libraries:
gem install nokogiri -- --use-system-libraries
...but was still failing when executing bundle install. So just configure bundler to also build Nokogiri using the system libraries:
bundle config build.nokogiri --use-system-libraries