I had to reinstall my local Bugzilla , so I took the opportunity to upgrade my local mysql as well.
This post contains my notes made during the process.
On OSX it is not always obvious which my.cnf file is used. You can find all my.cnf files on your system by issuing a find command
You can execute a mysql command to show in which locations you can place my.cnf files and in which order they are executed.