Implement --dos and --unix functions for getclip and putclip

This package doesn't really DO anything with the configure results.
If certain libraries aren't found, then some programs shouldn't be
built. Ditto certain functions.  But right now, everything that is
needed is checked for in configure, but no adjustments are made
to accomodate those results -- make will just fail.  This is surely
not the right way to do things.

what to do about wacky windows includes?  <shlobj.h> etc?

convert mkshortcut to popt.