ipv6: rename internal types and constants generated by cgo

To match up with other packages that work with IP protocol stack.

Change-Id: I1f4eb76051964766113914c9698233022e73d5eb
Reviewed-on: https://go-review.googlesource.com/30575
Run-TryBot: Mikio Hara <mikioh.mikioh@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
diff --git a/ipv6/zsys_netbsd.go b/ipv6/zsys_netbsd.go
index d6ec88e..bcada13 100644
--- a/ipv6/zsys_netbsd.go
+++ b/ipv6/zsys_netbsd.go
@@ -46,16 +46,16 @@
 	sysIPV6_PORTRANGE_HIGH    = 0x1
 	sysIPV6_PORTRANGE_LOW     = 0x2
 
-	sysSizeofSockaddrInet6 = 0x1c
-	sysSizeofInet6Pktinfo  = 0x14
-	sysSizeofIPv6Mtuinfo   = 0x20
+	sizeofSockaddrInet6 = 0x1c
+	sizeofInet6Pktinfo  = 0x14
+	sizeofIPv6Mtuinfo   = 0x20
 
-	sysSizeofIPv6Mreq = 0x14
+	sizeofIPv6Mreq = 0x14
 
-	sysSizeofICMPv6Filter = 0x20
+	sizeofICMPv6Filter = 0x20
 )
 
-type sysSockaddrInet6 struct {
+type sockaddrInet6 struct {
 	Len      uint8
 	Family   uint8
 	Port     uint16
@@ -64,21 +64,21 @@
 	Scope_id uint32
 }
 
-type sysInet6Pktinfo struct {
+type inet6Pktinfo struct {
 	Addr    [16]byte /* in6_addr */
 	Ifindex uint32
 }
 
-type sysIPv6Mtuinfo struct {
-	Addr sysSockaddrInet6
+type ipv6Mtuinfo struct {
+	Addr sockaddrInet6
 	Mtu  uint32
 }
 
-type sysIPv6Mreq struct {
+type ipv6Mreq struct {
 	Multiaddr [16]byte /* in6_addr */
 	Interface uint32
 }
 
-type sysICMPv6Filter struct {
+type icmpv6Filter struct {
 	Filt [8]uint32
 }