By default, the jamulus binary can function as:

- Client with GUI (default mode, X and jackd must be running)
- Server with GUI (-s option, only X must be running)
- Headless server (-s and -n options, neither X nor jackd required)

Even though the headless mode doesn't require a running X server,
it still requires the qt4 and X11 shared libraries. There's no way to
compile jamulus without these.

If you launch jamulus from the desktop start menu, you'll get the client.
If you want to run a server, you'll have to either run it from the command
line, or create a different launcher/shortcut for jamulus as a server.

If you want to run a headless server that starts at boot time (like
a regular daemon), currently the best way to do this is to call it
from /etc/rc.d/rc.local. There's no "daemon" option, so you'll have to
background it with &, and redirect stdout/stderr somewhere (see also
the -l <logfile> option).

If you *really* want to build a dedicated jamulus server, you can do
so by setting SERVERONLY=yes in the SlackBuild's environment. In this
case, you can ignore the REQUIRES="jack-audio-connection-kit" line in
the .info file.

The resulting jamulus binary will work exactly as the regular jamulus,
except it doesn't make sound nor accept audio input from your instrument.
It'll only be useful as a server (with -s and possibly also -n).

The *only* reason to ever do this is if you really *really* don't want
to install jack-audio-connection-kit for some reason.

For those who want to complain that I shouldn't have listed
jack-audio-connection-kit as required: It *is* required, for the *normal*
use case. Building without JACK support is a very specialized thing,
not useful to the general population of users.