xC: deal with so far unexpected multiline messages

And get rid of an outdated unmarked TODO comment.

xC.c

@@ -9075,12 +9075,21 @@ irc_autosplit_message (struct server *s, const char *message,
 			- 1 - (int) strlen (s->irc_user_host)
 			- 1 - fixed_part;
 
-	// However we don't always have the full info for message splitting
-	if (!space_in_one_message)
-		strv_append (output, message);
-	else if (!wrap_message (message, space_in_one_message, output, e))
-		return false;
-	return true;
+	// Multiline messages can be triggered through hooks and plugins.
+	struct strv lines = strv_make ();
+	cstr_split (message, "\r\n", false, &lines);
+	bool success = true;
+	for (size_t i = 0; i < lines.len; i++)
+	{
+		// We don't always have the full info for message splitting.
+		if (!space_in_one_message)
+			strv_append (output, lines.vector[i]);
+		else if (!(success =
+			wrap_message (lines.vector[i], space_in_one_message, output, e)))
+			break;
+	}
+	strv_free (&lines);
+	return success;
 }
 
 static void
@@ -9089,12 +9098,11 @@ send_autosplit_message (struct server *s,
 	const char *prefix, const char *suffix)
 {
 	struct buffer *buffer = str_map_find (&s->irc_buffer_map, target);
+
+	// "COMMAND target * :prefix*suffix"
 	int fixed_part = strlen (command) + 1 + strlen (target) + 1 + 1
 		+ strlen (prefix) + strlen (suffix);
 
-	// We might also want to preserve attributes across splits but
-	// that would make this code a lot more complicated
-
 	struct strv lines = strv_make ();
 	struct error *e = NULL;
 	if (!irc_autosplit_message (s, message, fixed_part, &lines, &e))