[CM] Snd 22.4

[bil at ccrma.Stanford.EDU]

Snd 22.4:

in Snd, johnm got the pulseaudio playback to work.

in s7:
defined? changed slightly; you may want to add #t=locally defined

generic append changed to make sequence handling more consistent,
   see s7test.scm ca line 10989 for examples


checked: Fedora 36 (gcc 12.0), openbsd 7.1

Thanks!:  Anders Vinjar, Michael Edwards, Fernando Oleo Blanco,
	  Rudy Adamkovic, johnm, Michael Mee