The CDI 1.0 spec states in 12.1. "Bean archives":

• In an application deployed as an ear, the container searches every bean archive bundled with or referenced by the ear, including bean archives bundled with or referenced by wars and EJB jars contained in the ear. The bean archives might be library jars, EJB jars, rars or war WEB-INF/classes directories.
• In an application deployed as a war, the container searches every bean archive bundled with or referenced by the war. The bean archives might be library jars or the WEB-INF/classes directory.
• In an application deployed as an EJB jar, the container searches the EJB jar, if it is a bean archive, and every bean archive referenced by the EJB jar.
• ...

Java EE 6 allows to reference installed libraries - see EE.8.2.2 "Installed Libraries".

However it seems installed libraries are not recognized as bean archives.