decoder/mad: convert to C++

Makefile.am

@@ -499,7 +499,9 @@ DECODER_LIBS = \
 DECODER_SRC =
 
 if HAVE_MAD
-libdecoder_plugins_a_SOURCES += src/decoder/mad_decoder_plugin.c
+libdecoder_plugins_a_SOURCES += \
+	src/decoder/MadDecoderPlugin.cxx \
+	src/decoder/MadDecoderPlugin.hxx
 endif
 
 if HAVE_MPG123

src/DecoderList.cxx

@@ -33,12 +33,12 @@
 #include "decoder/FfmpegDecoderPlugin.hxx"
 #include "decoder/GmeDecoderPlugin.hxx"
 #include "decoder/FaadDecoderPlugin.hxx"
+#include "decoder/MadDecoderPlugin.hxx"
 
 #include <glib.h>
 
 #include <string.h>
 
-extern const struct decoder_plugin mad_decoder_plugin;
 extern const struct decoder_plugin mpg123_decoder_plugin;
 extern const struct decoder_plugin sndfile_decoder_plugin;
 extern const struct decoder_plugin audiofile_decoder_plugin;

src/decoder/MadDecoderPlugin.hxx

+/*
+ * 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.
+ */
+
+#ifndef MPD_DECODER_MAD_HXX
+#define MPD_DECODER_MAD_HXX
+
+extern const struct decoder_plugin mad_decoder_plugin;
+
+#endif