Hi Marc Liyanage (http://www.entropy.ch/) gave me the right strings for the MySQL installed with his installer: --with-mysql-include=/usr/local/mysql/include --with-mysql-lib=/usr/local/mysql/lib It's also possible to compile it with the mysql that is installed with the 10.2 Server (after uncommenting have_library('m'); have_library('z') in extconf.rb): --with-mysql-include=/usr/include/mysql --with-mysql-lib=/usr/lib/mysql Thanks! Beat H.