"Your GStreamer installation is missing a plug-in."
https://groups.google.com/d/msg/clementine-player/tlJngoH0A_s/93HSiVjWwUEJ suggests all plugins should be included with the OS X distribution and that you may have to change some compile options to enable this (though that message is 3 years old, maybe something's changed since then). Appears that the "mikmod" plugin (which is in the GStreamer "good" plugins) should be able to play this.
"Your GStreamer installation is missing a plug-in."
https://groups.google.com/d/msg/clementine-player/tlJngoH0A_s/93HSiVjWwUEJ suggests all plugins should be included with the OS X distribution and that you may have to change some compile options to enable this (though that message is 3 years old, maybe something's changed since then). Appears that the "mikmod" plugin (which is in the GStreamer "good" plugins) should be able to play this.