anchor.diff:  
       // rec {
   
  -      meta = {
  -        description = "The default build environment for Unix packages in Nixpkgs";
  -      };
  -
  -      # Add a utility function to produce derivations that use this
  -      # stdenv and its shell.
  -      mkDerivation = attrs:
  -        let
  -          pos =
  -            if attrs.meta.description or null != null then
  -              unsafeGetAttrPos "description" attrs.meta
  -            else
  -              unsafeGetAttrPos "name" attrs;
  -          pos' = if pos != null then "‘" + pos.file + ":" + toString pos.line + "’" else "«unknown-file»";
  -        in
  -        if !allowUnfree
  -           && (let l = lib.lists.toList attrs.meta.license or []; in lib.lists.elem "unfree" l || lib.lists.elem "unfree-redistributable" l)
  -           && !allowUnfreePredicate attrs then
  -          throw ''
  -            Package ‘${attrs.name}’ in ${pos'} has an unfree license, refusing to evaluate. You can set
  -              { nixpkgs.config.allowUnfree = true; }
  -            in configuration.nix to override this. If you use Nix standalone, you can add
  -              { allowUnfree = true; }
  -            to ~/.nixpkgs/config.nix.''
  -        else if !allowBroken && attrs.meta.broken or false then
  -          throw "you can't use package ‘${attrs.name}’ in ${pos'} because it has been marked as broken"
  -        else if !allowBroken && attrs.meta.platforms or null != null && !lib.lists.elem result.system attrs.meta.platforms then
  -          throw "the package ‘${attrs.name}’ in ${pos'} is not supported on ‘${result.system}’"
  -        else
  -          lib.addPassthru (derivation (
  -            (removeAttrs attrs ["meta" "passthru" "crossAttrs"])
  -            // (let
  -              buildInputs = attrs.buildInputs or [];
  -              nativeBuildInputs = attrs.nativeBuildInputs or [];
  -              propagatedBuildInputs = attrs.propagatedBuildInputs or [];
  -              propagatedNativeBuildInputs = attrs.propagatedNativeBuildInputs or [];
  -              crossConfig = attrs.crossConfig or null;
  -            in
  -            {
  -              builder = attrs.realBuilder or shell;
  -              args = attrs.args or ["-e" (attrs.builder or ./default-builder.sh)];
  -              stdenv = result;
  -              system = result.system;
  -              userHook = config.stdenv.userHook or null;
  -              __ignoreNulls = true;
  -
  -              # Inputs built by the cross compiler.
  -              buildInputs = lib.optionals (crossConfig != null) (buildInputs ++ extraBuildInputs');
  -              propagatedBuildInputs = lib.optionals (crossConfig != null) propagatedBuildInputs;
  -              # Inputs built by the usual native compiler.
  -              nativeBuildInputs = nativeBuildInputs ++ lib.optionals (crossConfig == null) (buildInputs ++ extraBuildInputs');
  -              propagatedNativeBuildInputs = propagatedNativeBuildInputs ++
  -                lib.optionals (crossConfig == null) propagatedBuildInputs;
  -          }))) (
  -          {
  -            # The meta attribute is passed in the resulting attribute set,
  -            # but it's not part of the actual derivation, i.e., it's not
  -            # passed to the builder and is not a dependency.  But since we
  -            # include it in the result, it *is* available to nix-env for
  -            # queries.  We also a meta.position attribute here to
  -            # identify the source location of the package.
  -            meta = attrs.meta or {} // (if pos != null then {
  -              position = pos.file + ":" + (toString pos.line);
  -            } else {});
  -            passthru = attrs.passthru or {};
  -          } //
  -          # Pass through extra attributes that are not inputs, but
  -          # should be made available to Nix expressions using the
  -          # derivation (e.g., in assertions).
  -          (attrs.passthru or {}));
  +      meta.description = "The default build environment for Unix packages in Nixpkgs";
   
         # Utility flags to test the type of platform.
         isDarwin = system == "x86_64-darwin";
  
positive.code:       gcc
      ];
  
    # The stdenv that we are producing.
    result =
  
  
negative.code:       # Whether we should run paxctl to pax-mark binaries.
        needsPax = isLinux;
  
        inherit mkDerivation;
  
        # For convenience, bring in the library functions in lib/ so
        # packages don't have to do that themselves.
        inherit lib;
  