Long-standing problem in Socket module

Long-standing problem in Socket module

The Socket module provides an inet_aton() which isn't.  It's only
inet_addr().  The latter can't convert '255.255.255.255' (or
various equivalents).  This despite the fact that Socket.pm
claims that a conversion of that address is meaningful, which it
would be if we were using the real inet_aton().

Also, that address is properly the 'this-LAN' broadcast address,
also known as INADDR_BROADCAST.  That constant is missing from
Socket.xs, even though it provides the bogus INADDR_NONE, which
is merely an artifact of using inet_addr().  The all-ones
broadcast address is one of the few IP addresses which the spec
guarantees will be valid.  It's invalid for TCP, since it's a
broadcast address, but it's valid for ICMP and UDP.

The patch below changes Socket.xs to use a proper inet_aton()
conversion and adds the missing major INADDR constant of
INADDR_BROADCAST.  It includes (as the last item patched) the new
metaconfig unit used to make the changes to Configure,
config_h.SH, and Porting/Glossary.

p5p-msgid: <199612190418.XAA07291@Orb.Nashua.NH.US>