mpd: update to v0.21.16 and build with meson

One patch was dropped (probably not required anymore).

Old options have been dropped and new ones added. The order is as found
in meson_options.txt. mpd-mini and mpd-full retained their feature sets.

Signed-off-by: Andre Heider <a.heider@gmail.com>

sound/mpd/patches/210-support_raw_pcm_streams.patch

@@ -1,6 +1,6 @@
 --- a/src/decoder/plugins/FfmpegDecoderPlugin.cxx
 +++ b/src/decoder/plugins/FfmpegDecoderPlugin.cxx
-@@ -937,6 +937,7 @@ static const char *const ffmpeg_mime_typ
+@@ -775,6 +775,7 @@ static const char *const ffmpeg_mime_typ
  	"audio/qcelp",
  	"audio/vorbis",
  	"audio/vorbis+ogg",

sound/mpd/patches/220-handle_slow_server_stream_startup.patch

@@ -1,16 +0,0 @@
---- a/src/decoder/plugins/FfmpegDecoderPlugin.cxx
-+++ b/src/decoder/plugins/FfmpegDecoderPlugin.cxx
-@@ -478,6 +478,13 @@ ffmpeg_probe(DecoderClient *client, Inpu
- 
- 	unsigned char buffer[BUFFER_SIZE];
- 	size_t nbytes = decoder_read(client, is, buffer, BUFFER_SIZE);
-+
-+	if ((nbytes > 0) && (nbytes < 1024))
-+	{
-+		// Gobble some more data if header is small
-+		nbytes += decoder_read(client, is, buffer + nbytes, BUFFER_SIZE - nbytes);
-+	}
-+
- 	if (nbytes <= PADDING)
- 		return nullptr;
-