anchor.diff:        configFile2 = homeDir + "/.nixpkgs/config.nix";
   
         configExpr =
  -        if configFile != "" && pathExists configFile
  -        then import (toPath configFile)
  -        else if homeDir != "" && pathExists configFile2
  -        then import (toPath configFile2)
  +        if config_ != null then config_
  +        else if configFile != "" && pathExists configFile then import (toPath configFile)
  +        else if homeDir != "" && pathExists configFile2 then import (toPath configFile2)
           else {};
   
  +    in
         # allow both:
         # { /* the config */ } and
         # { pkgsOrig, pkgs, ... } : { /* the config */ }
  -      body = if builtins.isFunction configExpr
  +      if builtins.isFunction configExpr
           then configExpr { inherit pkgs pkgsOrig; }
           else configExpr;
  -    };
   
     # Return an attribute from the Nixpkgs configuration file, or
     # a default value if the attribute doesn't exist.
  
positive.code: , gccWithCC ? true
  , gccWithProfiling ? true
  
  }:
  
  
  let
  
  
negative.code: 
    allStdenvs = import ../stdenv {
      inherit system stdenvType;
      allPackages = args: import ./all-packages.nix ({ inherit config; } // args);
    };
  
    defaultStdenv = allStdenvs.stdenv;
  