Fix ALSA event encoding

snd_midi_event_encode encoes only first MIDI message. Instead,
keep pumping snd_midi_event_encode_byte and when it indicates a
fully-formed ALSA sequencer event seen, output it, and if any
events output after processing all bytes in the buffer, then drain
the output.
Still need to better understand whether need snd_midi_event_reset_encode
call is necessary.

mdep/linux/midi.c

@@ -275,22 +275,47 @@ void
 mdep_putnmidi(int n,char *p, Midiport * port)
 {
 	AlsaPortInfo * a = &outports[port->private1];
+	int have_event = 0;
+	int idx;
+	int ret;
 
+	/* Is this even required - doesn't parent handle running status
+	 * for the _output_ side? */
 	snd_midi_event_reset_encode (a->parser);
 
 	snd_seq_nonblock (seq, 0);
 
-	if (snd_midi_event_encode (a->parser, (unsigned char *)p, n, &a->event) >= 0) {
-		if (snd_seq_event_output (seq, &a->event) < 0) {
-			eprint("Hmm, write to MIDI device didn't write everything?\n");
-			keyerrfile("Hmm, write to MIDI device didn't write everything?\n");
-		} 
+	for (idx = 0; idx < n; ++idx)
+	{
+		ret = snd_midi_event_encode_byte(a->parser, p[idx], &a->event);
+		if (ret == 0)
+		{
+			/* Need more MIDI bytes to encode a complete ALSA sequencer event */
+			continue;
+		}
+		if (ret > 0)
+		{
+			/* Have fully encoded ALSA sequencer event - send it out */
+			have_event = 1;
+			if (snd_seq_event_output (seq, &a->event) < 0) {
+				eprint("Hmm, write to MIDI device didn't write everything?\n");
+				keyerrfile("Hmm, write to MIDI device didn't write everything?\n");
+			}
+		}
+		else 
+		{
+			eprint("snd_midi_event_encode_byte returned %d?", ret);
+			keyerrfile("snd_midi_event_encode_byte returned %d?", ret);
+		}
+	}
+
+	if (have_event)
+	{
 		if (snd_seq_drain_output (seq) < 0) {
 			eprint("Hmm, drain of MIDI device didn't write everything?\n");
 			keyerrfile("Hmm, drain of MIDI device didn't write everything?\n");
 		}
 	}
-
 	snd_seq_nonblock (seq, 1);
 }