[Haskell-beginners] cabal check complains about missing Setup.hs

When I run cabal check I get the following message: $ cabal check The following errors will cause portability problems on other environments: * The package is missing a Setup.hs or Setup.lhs script. Hackage would reject this package. ...but except this the package builds fine so far and the executable runs fine. So what does this exactly mean? ovidiu