Here are some things that should be done.

* My hacks to get around missing VPATH support in some makes do not work
  very well.  At the moment they require that _all_ dependencies are
  listed explicitly.  This is not good.  I think I may have require VPATH
  support in the future (GNU make supports it; Sun make does not).  That
  is also not good, but better than the current situation.  Alternatively,
  I could start creating makefiles from configuration scripts, but that
  doesn't work very well, either, since it loses on flexibility.

* --with-library should set --with-libshort as well, if not already set