anchor.diff:  
     prefixKey = "-prefix ";
   
  -  buildFlags = [ "world" ] ++ optional buildDoc "doc-html";
  +  buildFlags = [ "world" "byte" ] ++ optional buildDoc "doc-html";
   
  -  installTargets = [ "install" ] ++ optional buildDoc "install-doc-html";
  +  installTargets =
  +    [ "install" "install-byte" ] ++ optional buildDoc "install-doc-html";
   
  -  inherit doCheck;
  +  inherit doInstallCheck;
  +
  +  preInstallCheck = ''
  +    patchShebangs tools/
  +    patchShebangs test-suite/
  +  '';
  +
  +  installCheckTarget = [ "check" ];
   
   }
  
positive.code: 
  # nix-shell supports the --arg option (see Nix doc) that allows you for
  # instance to do this:
  # $ nix-shell --arg ocamlPackages "(import <nixpkgs> {}).ocamlPackages_latest" --arg buildIde false
  
  # You can also compile Coq and "install" it by running:
  # $ make clean # (only needed if you have left-over compilation files)
  # $ nix-build
  # at the root of the Coq repository.
  # nix-build also supports the --arg option, so you will be able to do:
  # $ nix-build --arg doCheck false
  # if you want to speed up things by not running the test-suite.
  # Once the build is finished, you will find, in the current directory,
  # a symlink to where Coq was installed.
  
negative.code:              ps.antlr4-python3-runtime ps.sphinxcontrib-bibtex ]))
       antlr4
  
    ] else []) ++ (if doInstallCheck then
  
      # Test-suite dependencies
      # ncurses is required to build an OCaml REPL
      optional (!versionAtLeast ocaml.version "4.07") ncurses
      ++ [
      python2
      rsync
      which
      ocamlPackages.ounit
  