problems with getaddrinfo() and _res.options

[Philip Blundell]

>As a consequence of these changes getaddrinfo() now does not return
>the IPv4 and IPv6 address of a host if AF_UNSPEC is passed in as the
>protocol.  This is another change, but again a useful one.

This will break all existing dual-stack applications.  Standard practice up 
until now has been to use AF_UNSPEC and expect to get back both IPv4 and IPv6 
addresses.  (I think this is true for all platforms, not just Linux.)

p.