Configure postInstall hook for ghc-heap-view and ghc-vis.
Configure postInstall hook for ghc-heap-view and ghc-vis.

Thanks to Gergely Risko for supplying this code in https://github.com/NixOS/nixpkgs/pull/809.

jb55/cabal2nix,bennofs/cabal2nix,dmalikov/cabal2nix,gridaphobe/cabal2nix,psibi/cabal2nix,Fuuzetsu/cabal2nix,spencerjanssen/cabal2nix