package/mpd: add libsidplay2 optional dependency

libsidplay2 is an optional dependency since version 0.15.0 and
https://github.com/MusicPlayerDaemon/MPD/commit/1136f6fb7a2a6a0a5bfba0dcf99410d1bbf04252

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/mpd/Config.in

@@ -165,6 +165,12 @@ config BR2_PACKAGE_MPD_OPUS
 	  Enable opus input support.
 	  Select this if you want to play back OPUS encoded files.
 
+config BR2_PACKAGE_MPD_SIDPLAY
+	bool "sidplay"
+	select BR2_PACKAGE_LIBSIDPLAY2
+	help
+	  Enable C64 SID support.
+
 config BR2_PACKAGE_MPD_TREMOR
 	bool "tremor"
 	depends on !BR2_PACKAGE_MPD_VORBIS

package/mpd/mpd.mk

@@ -241,6 +241,13 @@ else
 MPD_CONF_OPTS += -Dshout=disabled
 endif
 
+ifeq ($(BR2_PACKAGE_MPD_SIDPLAY),y)
+MPD_DEPENDENCIES += libsidplay2
+MPD_CONF_OPTS += -Dsidplay=enabled
+else
+MPD_CONF_OPTS += -Dsidplay=disabled
+endif
+
 ifeq ($(BR2_PACKAGE_MPD_SOUNDCLOUD),y)
 MPD_DEPENDENCIES += yajl
 MPD_CONF_OPTS += -Dsoundcloud=enabled