How to add xscreensaver service?

[Stefan Baums <baums@stefanbaums.com>]

Dear all,

I am trying to enable xscreensaver in my system configuration as
follows:

   (operating-system

    ...

    (services
       (append
        (list

         ...

         (screen-locker-service xscreensaver)

         ...

         %desktop-services))))

but reconfiguration fails with

   error: xscreensaver: unbound variable

Looking at various dotfiles online, the above looks right. What am
I missing? Do I need to add another line somewhere in my
system.scm to meet a dependency? I do have “xorg” in
“use-service-modules.”

All best,
Stefan