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

[Henning Thielemann]

On Tue, 19 Feb 2008, Christian Maeder wrote:

> In order to avoid several #ifdefs (maybe differently or suboptimal
> given) in user sources (to achieve 1.) such #ifdefs (or wrappers)
> should be part of the libraries (including the documentation for the
> license differences)!

Can Cabal-1.2's flag capability manage such a task?