Required changes for Connector/C already pushed. Connector/C uses environment variables MASTER_MYSOCK and MASTER_MYPORT (still open: host, user and schema).

Comments:

1. I presume new commands you've added to mysql-test/lib/generate-ssl-certs.sh don't generate new certificates, but only convert existing ones to something else? I mean, the expiration date is the same as for other certs? This script creates a bunch of certs, that all expire at the same day and this script is used to recreate them. If different certs will expire at different dates, it'll be inconvenient to maintain.
2. In C/C: Using CONFIGURE_FILE to replace @CERT_PATH@ is rather hackish. A proper way to do it is to use ADD_DEFINITIONS(-DCERT_PATH=${CERT_PATH} (or SET_PROPERTY to do it only for one file). But it's still wrong — you cannot use compile-time path in tests, because the tests could've been moved (e.g. packaged and installed). Use simply std_data, tests are run from the test dir. Or $MYSQL_TEST_DIR/std_data or even $SECURE_LOAD_PATH.