z8530_rtsdtr - Control the outgoing DTS/RTS line
void z8530_rtsdtr (struct z8530_channel *c, int set);
c The Z8530 channel to control; set 1 to set, 0 to clear
Sets or clears DTR/RTS on the requested line. All locking is handled by the caller. For now we assume all boards use the actual RTS/DTR on the chip. Apparently one or two don’t. We’ll scream about them later.