[Haskell-beginners] cabal optional build-depends

Hello the hmatrix package was splitte hmatrix -> hmatrix, hmatrix-gsl, ... for version > 0.16 I use Debian stable and need to support hmatrix 0.15 (with no split) and hmatrix >= 0.17 (splitted) I would like to know how to suport this in the cabal file only hmatrix if >= 0.15 && < 0.16 and hmatrix + hmatrix-gsl if hmatrix > 0.17 thanks for your help Frederic