Hydrogen is an advanced drum machine for GNU/Linux. 
It's main goal is to bring professional yet simple 
and intuitive pattern-based drum programming. 

Dependencies: 

libtar
jack-audio-connection-kit (optional, default=yes)
ladspa_sdk
liblrdf
lash (optional, default=yes)
portaudio (optional, default=no)
portmidi (optional, default=no)
scons

Optional deps can be set with the following flags:

JACK=yes|no
LASH=yes|no
PORTAUDIO=yes|no

PORTAUDIO=yes enables portmidi support.

*Note: if portaudio was built with jack support then
hydrogen will require it too.