rawmidi: do not abort when seeing the hint node

Add the hint node to the nodes that are allowed in rawmidi definitions,
and factor out the detection of such nodes into a common function.

src/rawmidi/rawmidi.c

@@ -987,3 +987,19 @@ ssize_t snd_rawmidi_read(snd_rawmidi_t *rawmidi, void *buffer, size_t size)
 	assert(buffer || size == 0);
 	return (rawmidi->ops->read)(rawmidi, buffer, size);
 }
+
+int snd_rawmidi_conf_generic_id(const char *id)
+{
+	static const char *ids[] = {
+		"comment",
+		"type",
+		"hint",
+	};
+	unsigned int k;
+
+	for (k = 0; k < sizeof ids / sizeof *ids; ++k) {
+		if (strcmp(id, ids[k]) == 0)
+			return 1;
+	}
+	return 0;
+}

src/rawmidi/rawmidi_hw.c

@@ -337,9 +337,7 @@ int _snd_rawmidi_hw_open(snd_rawmidi_t **inputp, snd_rawmidi_t **outputp,
 		const char *id;
 		if (snd_config_get_id(n, &id) < 0)
 			continue;
-		if (strcmp(id, "comment") == 0)
+		if (snd_rawmidi_conf_generic_id(id))
-			continue;
-		if (strcmp(id, "type") == 0)
 			continue;
 		if (strcmp(id, "card") == 0) {
 			err = snd_config_get_integer(n, &card);

src/rawmidi/rawmidi_local.h

@@ -57,3 +57,5 @@ int snd_rawmidi_hw_open(snd_rawmidi_t **input, snd_rawmidi_t **output,
 int snd_rawmidi_virtual_open(snd_rawmidi_t **inputp, snd_rawmidi_t **outputp,
 			     const char *name, snd_seq_t *seq_handle, int port,
 			     int merge, int mode);
+
+int snd_rawmidi_conf_generic_id(const char *id);

src/rawmidi/rawmidi_virt.c

@@ -411,9 +411,7 @@ int _snd_rawmidi_virtual_open(snd_rawmidi_t **inputp, snd_rawmidi_t **outputp,
 		const char *id;
 		if (snd_config_get_id(n, &id) < 0)
 			continue;
-		if (strcmp(id, "comment") == 0)
+		if (snd_rawmidi_conf_generic_id(id))
-			continue;
-		if (strcmp(id, "type") == 0)
 			continue;
 		if (strcmp(id, "slave") == 0) {
 			err = snd_config_get_string(n, &slave_str);