Patch by Kasper Dupont.  No CLA required for this size of patch.

"resolveip" program produces incorrect result if given a hostname
starting with a digit.  Someone seems to have thought that names 
can not have digits at the beginning.

Instead, use the resolver library to work out the rules of hostnames, 
as it will undoubtedly be better at it than we are.


configure.in:
  See if we need to a library for address lookups.
extra/resolveip.c:
  Don't use silly heuristic to know whether a string is a dotted
  quad.  Instead, pass the whole thing into the resolver and let
  its smarts do all the work.