The reduced 'darcs' derivation is supposed to be run-time independent of the
Haskell compiler. Unfortunately, this isn't quite true yet because the HTTP
package bakes its own store path into the library. This causes Darcs -- which
links the HTTP library statically -- to depend on 'HTTP', which in turn depends
on lot of other Haskell stuff. Patching HTTP to get rid of that reference looks
feasible, though.
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