renamed decoder plugin "mp3" to "mad"

src/Makefile.am

@@ -267,7 +267,7 @@ endif
 # decoder plugins
 
 if HAVE_MAD
-mpd_SOURCES += decoder/mp3_plugin.c
+mpd_SOURCES += decoder/mad_plugin.c
 endif
 
 if HAVE_MPCDEC

src/decoder/mp3_plugin.c → src/decoder/mad_plugin.c

@@ -1208,8 +1208,8 @@ static struct tag *mp3_tag_dup(const char *file)
 static const char *const mp3_suffixes[] = { "mp3", "mp2", NULL };
 static const char *const mp3_mime_types[] = { "audio/mpeg", NULL };
 
-const struct decoder_plugin mp3Plugin = {
-	.name = "mp3",
+const struct decoder_plugin mad_decoder_plugin = {
+	.name = "mad",
 	.init = mp3_plugin_init,
 	.stream_decode = mp3_decode,
 	.tag_dup = mp3_tag_dup,

src/decoder_list.c

@@ -26,7 +26,7 @@
 
 #include <string.h>
 
-extern const struct decoder_plugin mp3Plugin;
+extern const struct decoder_plugin mad_decoder_plugin;
 extern const struct decoder_plugin vorbis_decoder_plugin;
 extern const struct decoder_plugin flac_decoder_plugin;
 extern const struct decoder_plugin oggflac_decoder_plugin;
@@ -44,7 +44,7 @@ extern const struct decoder_plugin ffmpeg_plugin;
 
 static const struct decoder_plugin *const decoder_plugins[] = {
 #ifdef HAVE_MAD
-	&mp3Plugin,
+	&mad_decoder_plugin,
 #endif
 #ifdef HAVE_OGGVORBIS
 	&vorbis_decoder_plugin,