> I took a look at the nmap source and it is using SIOCGIFCONF
> incorrectly.  The following should help, but I'm running an old kernel
> on my notebook and can't test it.

At this point, isn't there far more software using SIOCGIFCONF
"incorrectly" than correctly? And if this is the case, shouldn't
the program for which the behavior was "fixed" (racoon, IIRC) be
modified instead?