installing mysql2 gem on osx info from stackoverflow.com

http://stackoverflow.com/questions/4115126/ruby-gem-mysql2-install-failing

You need the MySQL development headers for mysql2 to properly compile. This is needed, because much of the functionality is written in C and subsequently linked against MySQL.

A solution is to either point the gem installer to your mysql install folder explicitly like so

gem install mysql2 -- --with-mysql-dir=/usr/local/mysql# or where ever you installed your mysql server to

or by installing a mysql server to a known location (e.g. by using homebrew.) and then installing the gem

# install the mysql server locally
brew install mysql# install the gem
gem install mysql2

Both approaches require you to have XCode installed to have the required GCC compiler.