ange-ftp and ipv6

[Chong Yidong]

I've been trying to reproduce the following bug from FOR-RELEASE:

> ** Ange-ftp should ignore irrelevant IPv6 errors:
> ...
> The problem is that the DNS first gives an IPV6 address. However our
> router doesn't do IPV6. Ftp then falls back to IPV4:
>
> ftp> open ftp.nluug.nl
> Trying 2001:610:1:80aa:192:87:102:36...
> ftp: connect to address 2001:610:1:80aa:192:87:102:36: No route to host
> Trying 192.87.102.36...
> Connected to ftp.nluug.nl.
>
> Ange-ftp chokes on the `No route to host' message and doesn't look any
> further.

My DNS also issues an IPV6 address, but the ftp program I use (BSD ftp on
a Red Hat box) fails silently on IPV6 without issuing a "No route to host"
message:

  ftp> open ftp.nluug.nl
  Trying 2001:610:1:80aa:192:87:102:36...
  Trying 192.87.102.36...
  Connected to ftp.nluug.nl (192.87.102.36).

Does anyone know a simple way to reproduce this bug?

In any case, could it be fixed by replacing "No route to host" with "No
route to host\n[^T]" in ange-ftp-gateway-fatal-msgs, to distinguish
between "No route to host\nTrying..." and a real error?