[LAU] Header missing to build Zita AT 1

[Ralf Mardorf]

PS: The only issue now seems to be, that Qtractor doesn't support
individual MIDI IOs or that I don't know what to do, to get individual
ports. This already is an annoyance for me, when not using AT1. A quick
test, Qtractor MIDI out connected to AT1 MIDI in (AT1 audio wasn't
connected) showed, that AT1 receives in omni mode.

:(

So I at least need to add a MIDI filter between Qtractor and AT1. Is
there a lightweight command line filter that can filter out the MIDI
events of a single channel?