non-linux: Apply RFC3542 obsoletion of RFC2292 macros

	RFC2292 macros were obsoleted by RFC3542, and should not be exposed
	any more. Notably since IPV6_PKTINFO has been reintroduced with a
	completely different API.

	* bits/in.h (IPV6_PKTINFO): Rename to IPV6_2292PKTINFO.
	(IPV6_HOPOPTS): Rename to IPV6_2292HOPOPTS.
	(IPV6_DSTOPTS): Rename to IPV6_2292DSTOPTS.
	(IPV6_RTHDR): Rename to IPV6_2292RTHDR.
	(IPV6_PKTOPTIONS): Rename to IPV6_2292PKTOPTIONS.
	(IPV6_HOPLIMIT): Rename to IPV6_2292HOPLIMIT.
	(IPV6_RECVPKTINFO): New macro.
	(IPV6_PKTINFO): New macro.