[CM] convolution

[Bill Schottstaedt]

> working through the examples
> what does
> WARNING can't do lisp sound file IO in no-ffi mode mean?

It means that you can't use outa outside the run macro in a
version of clm that doesn't use the foreign function interface
and is not pure lisp (i.e. clisp primarily).  In the convolution-based
reverb in cnv.ins, it makes an impulse response and puts it in
a file:

	(loop for i from start-samp below len do
	  (let ((sum 0.0))
	    (dotimes (i 10) (incf sum (- (random .4) .2)))
	    ;;Gaussian noise -- 0 centered much better than pure positive case
	    (outa i (* (env fe) sum) ofile)))
	(close-output ofile))

This code won't work in no-ffi mode.