udp: support for IPv6 addresses

Hello,

Do the udpsrc and udpsink elements support IPv6? When specifying localhost as the host for the udpsink element with the below /etc/hosts file, it seems like gstreamer is not able to handle the ::1 IPv6 address. Not sure if this is a 🐛 or if IPv6 is just not supported yet.

/etc/hosts

127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4
::1         localhost localhost.localdomain localhost6 localhost6.localdomain6

Gstreamer logs

INFO  multiudpsink gstmultiudpsink.c:1387:gst_multiudpsink_start:<udpsink1> Failed to create IPv6 socket: Unable to create socket: Address family not supported by protocol
WARN  multiudpsink gstmultiudpsink.c:1285:gst_multiudpsink_configure_client:<udpsink1> error: Invalid address family (got 10)