package/vlc: add optional dependency to libupnp18

Upstream added support for libupnp-1.8:
http://git.videolan.org/?p=vlc/vlc-2.2.git;a=commit;h=825dca78be3a81e2a1c5d04137aa01b1cb32dfd3

Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/vlc/vlc.mk

@@ -288,6 +288,13 @@ else
 VLC_CONF_OPTS += --disable-upnp
 endif
 
+ifeq ($(BR2_PACKAGE_LIBUPNP18),y)
+VLC_CONF_OPTS += --enable-upnp
+VLC_DEPENDENCIES += libupnp18
+else
+VLC_CONF_OPTS += --disable-upnp
+endif
+
 ifeq ($(BR2_PACKAGE_LIBVNCSERVER),y)
 VLC_CONF_OPTS += --enable-vnc
 VLC_DEPENDENCIES += libvncserver