darcs patch: [PROOF OF CONCEPT] build readline package with libedit

[Christian Maeder]

Judah Jacobson wrote:
> I'll work on making a new patch which adds back all of the
> functionality that libedit supports (including what's needed for
> shellac-readline).

Let me again stress, that we should make all options work and let us or
others decide later on, which option is best for them or which should be
the default (taken by configure without arguments).

Christian