option to use mariadb_config instead of mysql_config

[jhinghaus]

I use MySQLdb1 on Ubuntu 16 to connect an old MySQL 3.23.
The libmysqlclient20 used as a standard does not support the old version, but libmariadbclient does.
Removing libmysqlclient and installing libmariadbclient makes the pip install fail because there is no mysql_config.
Faking a mysql_config with ln -s /usr/bin/mariadb_config mysql_config does the job as mariadb_config seems to be compatible enough.

Is there a chance for some kind of option to use mariadb_config or am I looking in the wrong spot?