Groovy is a dynamic language for the Java platform.

This sets GROOVY_HOME=/usr/<libdir>/groovy and PATH to include
/usr/<libdir>/groovy/bin.

The installation is like Java Runtime/SDK, in that it places everything by
default in /usr/<libdir>/groovy.

The lib directory is set dependent upon the package architecture: /usr/lib
on x86 and /usr/lib64 on x86_64.