rabbitmq-tcl is written under a permissive BSD-2-Clause license, but we linked to exceptions4c, which was previously released under the LGPL, to prevent crashes in software that depends on it when issues occur.

The author has since relicensed the latest version of the library under the more permissive Apache License.

This resolves the licensing issue for exceptions4c.

References:

• 0d140c05a4d17c99

Plan

• In vendor/e4c upgrade to exceptions4c 4.0
• Check https://github.com/guillermocalvo/exceptions4c/releases and https://exceptions4c.guillermo.dev/ to determine if code migration is needed
• Remove comments about licensing in the README