windows: add IP_HDRINCL, IP_PKTINFO, IPV6_PKTINFO

These will be used to replace the respective local definitions in
the golang.org/x/net package.

Change-Id: Ieae8908a87ee7df1ca43683e7e921128bff90b8d
Reviewed-on: https://go-review.googlesource.com/c/sys/+/301690
Trust: Tobias Klauser <tobias.klauser@gmail.com>
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

windows/types_windows.go

@@ -1020,6 +1020,7 @@ const (
 
 	// cf. http://support.microsoft.com/default.aspx?scid=kb;en-us;257460
 
+	IP_HDRINCL         = 0x2
 	IP_TOS             = 0x3
 	IP_TTL             = 0x4
 	IP_MULTICAST_IF    = 0x9
@@ -1027,6 +1028,7 @@ const (
 	IP_MULTICAST_LOOP  = 0xb
 	IP_ADD_MEMBERSHIP  = 0xc
 	IP_DROP_MEMBERSHIP = 0xd
+	IP_PKTINFO         = 0x13
 
 	IPV6_V6ONLY         = 0x1b
 	IPV6_UNICAST_HOPS   = 0x4
@@ -1035,6 +1037,7 @@ const (
 	IPV6_MULTICAST_LOOP = 0xb
 	IPV6_JOIN_GROUP     = 0xc
 	IPV6_LEAVE_GROUP    = 0xd
+	IPV6_PKTINFO        = 0x13
 
 	MSG_OOB       = 0x1
 	MSG_PEEK      = 0x2