Avoid direct use of `/usr/local' in pkg/MESSAGE and use `${PREFIX}'
literally instead.
Indicated by: portlint
* Introducing `MESSAGE_SUB' might be a good idea to do substitutions
* in order to give proper instructions.
As the new version of esecanna has introduced dynamic module loading
mechanism, the port esecanna-vje30 has to be split into two ports
named esecanna and esecanna-module-vje30
PR: ports/16972
Submitted by: knu@idaemons.org
