implement PWT buzzer driver The piece implemented here is the low-level driver component; there will also be a higher-level buzzer melody player service, to be implemented in RiViera land, that will be the sole caller of PWT API functions provided by the present driver.

clean:	FRC
	rm -f fwimage.* ramimage.* str2ind.* link.cmd link_ram.cmd
	rm -f build_date.* flash-script
	for i in ${SUBDIR}; do (cd $$i; ${MAKE} ${MFLAGS} clean); done