anchor.diff:  
     See trace/nixpkgs/trunk/pkgs/top-level/builder-defs.nix for some predefined build steps
   
  +  Attention:
  +
  +  let
  +    pkgs = (import /etc/nixos/nixpkgs/pkgs/top-level/all-packages.nix) {};
  +  in let
  +    inherit (pkgs.stringsWithDeps) fullDepEntry packEntry noDepEntry textClosureMap;
  +    inherit (pkgs.lib) id;
  +
  +    nameA = noDepEntry "Text a";
  +    nameB = fullDepEntry "Text b" ["nameA"];
  +    nameC = fullDepEntry "Text c" ["nameA"];
  +
  +    stages = {
  +      nameHeader = noDepEntry "#! /bin/sh \n";
  +      inherit nameA nameB nameC;
  +    };
  +  in
  +    textClosureMap id stages
  +    [ "nameHeader" "nameA" "nameB" "nameC"
  +      nameC # <- added twice. add a dep entry if you know that it will be added once only [1]
  +      "nameB" # <- this will not be added again because the attr name (reference) is used
  +    ]
  +
  +  # result: Str("#! /bin/sh \n\nText a\nText b\nText c\nText c",[])
  +
  +  [1] maybe this behaviour should be removed to keep things simple (?)
   */
   
   {stdenv, lib}:
  
positive.code: 
    You define you custom builder script by adding all build steps to a list.
    for example:
  	builder = writeScript "fsg-4.4-builder"
  		(textClosure [doUnpack addInputs preBuild doMake installPhase doForceShare]);
  
    a step is defined by noDepEntry, fullDepEntry or packEntry.
    To ensure that prerequisite are met those are added before the task itself by
  
negative.code:   fullDepEntry = text: deps: {inherit text deps;};
    packEntry = deps: {inherit deps; text="";};
  
    # Old names - don't use. Will be removed soon. There are no more occurences in nixpkgs/nixos
    FullDepEntry = fullDepEntry;
    PackEntry = packEntry;
    
  