anchor.diff:    al = appendConfigureFlag super.al "--extra-include-dirs=${pkgs.openal}/include/AL";
   
     # Depends on code distributed under a non-free license.
  +  accelerate-cublas = dontDistribute super.accelerate-cublas;
  +  accelerate-cuda = dontDistribute super.accelerate-cuda;
  +  accelerate-cufft  = dontDistribute super.accelerate-cufft;
  +  accelerate-examples = dontDistribute super.accelerate-examples;
  +  accelerate-fft = dontDistribute super.accelerate-fft;
  +  accelerate-fourier-benchmark = dontDistribute super.accelerate-fourier-benchmark;
     bindings-yices = dontDistribute super.bindings-yices;
  +  cublas = dontDistribute super.cublas;
  +  cufft = dontDistribute super.cufft;
  +  gloss-accelerate = dontDistribute super.gloss-accelerate;
  +  gloss-raster-accelerate = dontDistribute super.gloss-raster-accelerate;
  +  libnvvm = dontDistribute super.libnvvm;
  +  Obsidian = dontDistribute super.Obsidian;
  +  patch-image = dontDistribute super.patch-image;
     yices = dontDistribute super.yices;
     yices-easy = dontDistribute super.yices-easy;
     yices-painless = dontDistribute super.yices-painless;
  
positive.code:   tz = overrideCabal super.tz (drv: { preConfigure = "export TZDIR=${pkgs.tzdata}/share/zoneinfo"; });
  
    # Deprecated upstream and doesn't compile.
    llvm-base = markBroken super.llvm-base;
    bytestring-arbitrary = dontDistribute (addBuildTool super.bytestring-arbitrary self.llvm);
    objectid = dontDistribute super.objectid;
    saltine-quickcheck = dontDistribute super.saltine-quickcheck;
  
    # https://ghc.haskell.org/trac/ghc/ticket/9625
    vty = dontCheck super.vty;
  
negative.code:   haroonga-httpd = markBroken super.haroonga-httpd;
  
    # Cannot find pkg-config data for "webkit-1.0".
    lambdacat = dontDistribute super.lambdacat;
    manatee-all = dontDistribute super.manatee-all;
    manatee-browser = dontDistribute super.manatee-browser;
    manatee-reader = dontDistribute super.manatee-reader;
    markup-preview = dontDistribute super.markup-preview;
    spike = dontDistribute super.spike;
    tianbar = dontDistribute super.tianbar;
    web-browser-in-haskell = dontDistribute super.web-browser-in-haskell;
    webkit = markBroken super.webkit; # .override { webkit = pkgs.webkitgtk24x; };
    webkit-javascriptcore = dontDistribute super.webkit-javascriptcore;
    websnap = markBroken super.websnap; # .override { webkit = pkgs.webkitgtk24x; };
  
    # Build is broken and no contact info available.
    hopenpgp-tools = markBroken super.hopenpgp-tools;
  