CommandLine: new command line parser

This implementation behaves mostly identical to old parser.
Few observable differences:
- There are no option groups (single group is used for all options)
- Option --stdout is hidden (it has been obsolete for a long time)
- MPD executable name (mpd) is hardcoded for simplicity

src/util/OptionParser.cxx

@@ -0,0 +1,59 @@
+/*
+ * Copyright (C) 2003-2013 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "OptionParser.hxx"
+#include "OptionDef.hxx"
+
+#include <string.h>
+
+bool OptionParser::CheckOption(const OptionDef &opt)
+{
+	assert(option != nullptr);
+
+	if (is_long)
+		return opt.HasLongOption() &&
+		       strcmp(option, opt.GetLongOption()) == 0;
+
+	return opt.HasShortOption() &&
+	       option[0] == opt.GetShortOption() &&
+	       option[1] == '\0';
+}
+
+bool OptionParser::ParseNext()
+{
+	assert(HasEntries());
+	char *arg = *argv;
+	++argv;
+	--argc;
+	if (arg[0] == '-') {
+		if (arg[1] == '-') {
+			option = arg + 2;
+			is_long = true;
+		}
+		else {
+			option = arg + 1;
+			is_long = false;
+		}
+		option_raw = arg;
+		return true;
+	}
+	option = nullptr;
+	option_raw = nullptr;
+	return false;
+}