The JEE6 API JARs from OpenEJB is Apache 2.0 licensed.
Bundling this will cost ~1 MiB of extra distribution space, but avoid build-time dependencies on the app server.
Bonus points for getting the ejbca.sh/bat EJB CLI jars runtime from the EJBCA CLI script (like SignServer) so we only need appserver.home set for install/deploy.
(This helps when JBoss EAP is updated and the JARs that we need go away. Also we ensure that we stay at JEE6 once JEE7 compatible appservers start to appear at developer machines.)