I'm upgrading a webapp server from Tomcat 7 to Tomcat 8 on Ubuntu 16.04.
At installation, Tomcat 7 creates a directory `/var/lib/tomcat7/common/`.
When Tomcat 8 is installed, however, the `/var/lib/tomcat8/` directory it
creates does not include a `common/` directory, and the deployment script
complains that it isn't there.
build.xml:129: /var/lib/tomcat8/common/lib does not exist.
I've been searching for a day and have found exactly zero documentation on
this, including on the official 8.0 migration guide (
https://tomcat.apache.org/migration-8.html).
What is the `/var/lib/tomcat7/common/` directory for, and why does Tomcat 8
not have one?