anchor.diff:    src = fetchFromGitHub {
       owner  = "tamarin-prover";
       repo   = "tamarin-prover";
  -    rev    = "120c7e706f3e1d4646b233faf2bc9936834ed9d3";
  -    sha256 = "064blwjjwnkycwgsrdn1xkjya976wndpz9h5pjmgjqqirinc8c5x";
  +    rev    = "ab8a155452e9e9c57ccb4bbe1b94d7677ea5ce21";
  +    sha256 = "02ycxxkcpc0dzybaq63viciydq1ik8wiv2blk8mvnz3ssxw3sjik";
     };
   
     # tamarin has its own dependencies, but they're kept inside the repo,
  
positive.code:   enableSharedExecutables = false;
    postFixup = "rm -rf $out/lib $out/nix-support $out/share/doc";
  
    # wrap the prover to be sure it can find maude, sapic, etc
    executableToolDepends = [ makeWrapper which maude graphviz sapic ];
    postInstall = ''
  
negative.code: 
    executableHaskellDepends = (with haskellPackages; [
      base binary binary-orphans blaze-builder blaze-html bytestring
      cmdargs conduit containers monad-control deepseq directory fclabels file-embed
      filepath gitrev http-types HUnit lifted-base mtl parsec process
      resourcet safe shakespeare tamarin-prover-term
      template-haskell text threads time wai warp yesod-core yesod-static
  