getaddrinfo(), but only if a corresponding call to socket() returned one of
three *NOSUPPORT errno codes. A Redhat 6.2 system was observed returning
EINVAL instead so it never went on to try IPv4. This update adds EINVAL to
the list. Question: why not always continue through the list regardless of
what errno is?
case EPROTONOSUPPORT:
case EAFNOSUPPORT:
case EPFNOSUPPORT:
+ case EINVAL:
/* See if there's another address that will work... */
continue;
}