anchor.diff:        diagrams-svg      = super.callHackage "diagrams-svg" "1.4.1" {};
         dual-tree         = super.callHackage "dual-tree" "0.2.1" {};
         fast-math         = super.callHackage "fast-math" "1.0.2" {};
  -      glib              = super.callHackage "glib" "0.13.5.0"  {};
  -      gtk2hs-buildtools = super.callHackage "gtk2hs-buildtools" "0.13.2.2" {};
  +      gtk2hs-buildtools = super.callHackage "gtk2hs-buildtools" "0.13.3.0" {};
         magic             = super.callHackage "magic" "1.1" {};
         mfsolve           = super.callHackage "mfsolve" "0.3.2.0" {};
  -      pango             = super.callHackage "pango" "0.13.4.0" {};
         statestack        = super.callHackage "statestack" "0.2.0.5" {};
         static-canvas     = super.callHackage "static-canvas" "0.2.0.3" {};
         svg-builder       = super.callHackage "svg-builder" "0.1.0.2" {};
  
positive.code:     ihaskell
      ihaskell-aeson
      ihaskell-blaze
      # ihaskell-charts
      # ihaskell-diagrams
      ihaskell-gnuplot
      ihaskell-hatex
      ihaskell-juicypixels
  
negative.code:         "ihaskell-widgets"
        ]);
    haskellPackages = nixpkgs.haskell.packages.ghc821.override {
      overrides = self: super: {
        ihaskell       = nixpkgs.haskell.lib.overrideCabal (
                         self.callCabal2nix "ihaskell"          ihaskell-src       {}) (_drv: {
          postPatch = let
  