[project @ 2000-04-21 18:07:46 by panne]

I've bitten the bullet and cleaned up the mess around Readline. There
are actually questions to answer by autoconf:

   * Are the headers available for compilation?
   * Are the libraries (and which) available for linking?

Note that in the second case it should be the libraries on the machine
which GHC is *installed* on, not the ones on which it was compiled.
GhcLibsWithReadline is now automagically set if the headers are found,
but this can still be overridden.