anchor.diff:  , systems ? [ "i686-linux" "x86_64-linux" ]
   , buildForAmiga ? false
   , amigaosenvPath ? <amigaosenv>
  +, libiff ? { outPath = ./.; rev = 1234; }
  +, officialRelease ? false
   }:
   
   let
  
positive.code:       };
        
      build =
        { tarball ? jobs.tarball {} }:
        
        (pkgs.lib.genAttrs systems (system:
          with import nixpkgs { inherit system; };
          
  
negative.code:   
    jobs = rec {
      tarball =
        with pkgs;
  
        releaseTools.sourceTarball {
  