net001 test failure

[Bryan O'Sullivan]

Simon Marlow wrote:
> The test net001 from the network package is failing on my RedHat 9 box, 
> so I went investigating.  Bear in mind I'm completely ignorant of IPV6.  
> This test invokes
> 
>   Network.listenOn (PortNumber 22222)
> 
> and gets:
> 
>   socket: unsupported operation (Address family not supported by protocol)
> 
> This machine has getaddrinfo(), so the IPV6 support is enabled.

It appears that Red Hat 9's IPv6 support is completely broken.  I think 
the simplest thing to do about this is to make an explicit check for RH9 
in the configure script and turn off IPv6 support if we detect it.  Red 
Hat EOLed RH9 years ago, so I don't think investing much effort in it is 
warranted.

Does this seem reasonable?

	<b