X11 display code:
 - at end-of-section it forgets about display window.
   -> allocate and deallocate displays as notes are turned on and off.
   -> get storage from auxalloc() so that it will be freed at end-of-section.
      (for which we need the instrument number and/or structure )
 - fix out-by-one problem in scaling of centre-axis displays
 - include code to pause after every frame on a command-line option.

dspfft
	dumps core on size == 2048 on Sun 3 and 4.
	The same code with size==1024 works.

	ORCHESTRA:
	instr 1
	a1	rand	10
		dspfft	a1,1/25,2048
	endin

	SCORE:
	i1 0 10