[Haskell-beginners] problem cabal install'ing hmatrix

$ cabal install hmatrix Resolving dependencies... Configuring hmatrix-0.5.1.1... Preprocessing library hmatrix-0.5.1.1... running dist/build/Numeric/GSL/Special/Internal_hsc_make failed command was: dist/build/Numeric/GSL/Special/Internal_hsc_make

dist/build/Numeric/GSL/Special/Internal.hs cabal: Error: some packages failed to install: hmatrix-0.5.1.1 failed during the building phase. The exception was: exit: ExitFailure 1

What should I do to diagnose/resolve this problem? I'm on Gentoo/amd64 and have also posted this question in the gentoo forums. TIA for any help and pointers, Erik