This has happened more that once so I thought I’d document the fix. “gem install nokogori” produces the following error
ERROR: Error installing nokogiri: ERROR: Failed to build gem native extension.
A quick check of the log file
~/.rvm/gems/ruby-1.9.3-p551/extensions/x86_64-darwin-14/1.9.1/nokogiri-1.6.8/mkmf.log shows that the package libiconv was not found.
On mac os, installing apple-gcc42 does the trick. Run
brew install apple-gcc42 and try
bundle install again