TODO for arpsend

Port to other platforms; stop ignoring most of what autoconf learns.
(Although the arpsend build process is autoconf-based, at
this time arpsend ignores almost everything autoconf discovers
about your system.  The product was developed on Solaris 7 with gcc 2.95.2,
and has not been ported to other platforms.  Despite the use of autoconf, the
code merrily makes assumptions that are only valid on Solaris 7.)
The use of autoconf here is mostly to provide a framework in case the
product is ported to other platforms in the future.

If you specify a target IP address of 255.255.255.255, you are warned
that this is the IP limited broadcast address (correct), but then also
warned it is an IP experimental (Class E) address (wrong).
And you are also warned it is on the loopback network (wrong). 
Fix the warnings.