syscall: make route_bsd.go 64-bit clean on every netbsd

[mikioh]

On 32-bit NetBSD, Addrs of net.Interface or net.InterfaceAddrs never return correct IPv6
interface addresses but 64-bit NetBSD is fine because,

1) I didn't noticed but NetBSD did a cleanup of 64-bit aligned access to routing
facilities
http://cvsweb.netbsd.org/bsdweb.cgi/src/sys/net/rtsock.c?rev=1.133&;content-type=text/x-cvsweb-markup&only_with_tag=MAIN

2) On 32-bit systems, sometimes they don't set address families correctly, still we see
AF_UNSPEC in sockaddrs, unlike the 64-bit systems

So, the fix should be;
- 64-bit alignment routing facility access on every NetBSD platforms
- find out and remark preferred address family

[mikioh]

Comment 1:

% uname -a
NetBSD vm3 6.1.1 NetBSD 6.1.1 (GENERIC) i386
% go test -v -run=Interf
=== RUN TestInterfaces
--- PASS: TestInterfaces (0.00 seconds)
        interface_test.go:59: table: len/cap = 2/2
        interface_test.go:76: "wm0": flags "up|broadcast|multicast", ifindex 1, mtu 1500
        interface_test.go:77:   hardware address "..."
        interface_test.go:125:  interface address "<nil>"
        interface_test.go:125:  interface address "<nil>"
        interface_test.go:125:  interface address "172.16.220.13/24"
        interface_test.go:76: "lo0": flags "up|loopback|multicast", ifindex 2, mtu 33192
        interface_test.go:77:   hardware address ""
        interface_test.go:125:  interface address "<nil>"
        interface_test.go:125:  interface address "127.0.0.1/8"
        interface_test.go:125:  interface address "<nil>"
        interface_test.go:125:  interface address "<nil>"
=== RUN TestInterfaceAddrs
--- PASS: TestInterfaceAddrs (0.00 seconds)
        interface_test.go:88: table: len/cap = 7/8
        interface_test.go:125:  interface address "<nil>"
        interface_test.go:125:  interface address "<nil>"
        interface_test.go:125:  interface address "172.16.220.13/24"
        interface_test.go:125:  interface address "<nil>"
        interface_test.go:125:  interface address "127.0.0.1/8"
        interface_test.go:125:  interface address "<nil>"
        interface_test.go:125:  interface address "<nil>"

[mikioh]

Comment 2:

This issue was closed by revision 9a79472.

Status changed to Fixed.