OpenImageIO/oiio — pull request #621 by lgritz (2013-06-22 16:48:35+00:00)
Title: OIIO attribute "plugins_override" 

OIIO attribute "plugins_override" causes externally found plugins to override
built-in plugins with the same name (instead of the default of built-in
plugins always winning). Also can be overridden with the
OIIO_PLUGINS_OVERRIDE environment variable.