Installing Ruby MySQL gem on Mac OS X Leopard
Thanks to this post, I discovered how to install the MySQL ruby gem on Mac OS X:
You must be using the x86 variant of MySQL, not x86_64, apparently. Then:
sudo env ARCHFLAGS="-arch i386" gem install mysql -- \ --with-mysql-dir=/usr/local/mysql --with-mysql-lib=/usr/local/mysql/lib \ --with-mysql-include=/usr/local/mysql/include

A colleague just found this:
sudo env ARCHFLAGS=”-arch i386″ gem install mysql — –with-mysql-config=/usr/local/mysql/bin/mysql_config
I believe they are essentially equivalent, however this new one is more elegant.