Add support for resolving IPv4 address literals for DNS64 support
Submitted by joe..@..il.com
The source of creating this bug can be found in the discussion here: http://gstreamer-devel.966125.n4.nabble.com/NAT64-support-td4681208.html.
When on NAT64 networks, passing an IPv4 address literal does not get automatically resolved to its IPv6 equivalent so streaming via elements such as udpsink or udpsrc doesn't work. This is required for iOS as described here: https://developer.apple.com/library/content/documentation//NetworkingInternetWeb/Conceptual/NetworkingOverview/UnderstandingandPreparingfortheIPv6Transition/UnderstandingandPreparingfortheIPv6Transition.html.