unix: add Inet4Pktinfo type on solaris

Change-Id: I4f18b5d98697120a16b56657a012d7ab5fe1b83c
Reviewed-on: https://go-review.googlesource.com/c/sys/+/213399
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

unix/types_solaris.go

@@ -158,6 +158,8 @@ type Msghdr C.struct_msghdr
 
 type Cmsghdr C.struct_cmsghdr
 
+type Inet4Pktinfo C.struct_in_pktinfo
+
 type Inet6Pktinfo C.struct_in6_pktinfo
 
 type IPv6MTUInfo C.struct_ip6_mtuinfo
@@ -175,6 +177,7 @@ const (
 	SizeofIPv6Mreq         = C.sizeof_struct_ipv6_mreq
 	SizeofMsghdr           = C.sizeof_struct_msghdr
 	SizeofCmsghdr          = C.sizeof_struct_cmsghdr
+	SizeofInet4Pktinfo     = C.sizeof_struct_in_pktinfo
 	SizeofInet6Pktinfo     = C.sizeof_struct_in6_pktinfo
 	SizeofIPv6MTUInfo      = C.sizeof_struct_ip6_mtuinfo
 	SizeofICMPv6Filter     = C.sizeof_struct_icmp6_filter

unix/ztypes_solaris_amd64.go

@@ -211,6 +211,12 @@ type Cmsghdr struct {
 	Type  int32
 }
 
+type Inet4Pktinfo struct {
+	Ifindex  uint32
+	Spec_dst [4]byte /* in_addr */
+	Addr     [4]byte /* in_addr */
+}
+
 type Inet6Pktinfo struct {
 	Addr    [16]byte /* in6_addr */
 	Ifindex uint32
@@ -236,6 +242,7 @@ const (
 	SizeofIPv6Mreq         = 0x14
 	SizeofMsghdr           = 0x30
 	SizeofCmsghdr          = 0xc
+	SizeofInet4Pktinfo     = 0xc
 	SizeofInet6Pktinfo     = 0x14
 	SizeofIPv6MTUInfo      = 0x24
 	SizeofICMPv6Filter     = 0x20