anchor.diff:    openfx = callPackage ../development/libraries/openfx {};
   
     openimageio = callPackage ../applications/graphics/openimageio {
  -    stdenv = overrideCC stdenv buildPackages.gcc6;
  +    stdenv = gcc6Stdenv;
     };
   
     openimageio2 = callPackage ../applications/graphics/openimageio/2.x.nix { };
  
positive.code: 
    opal = callPackage ../development/libraries/opal {
      ffmpeg = ffmpeg_2;
      stdenv = overrideCC stdenv buildPackages.gcc6;
    };
  
    openh264 = callPackage ../development/libraries/openh264 { };
  
negative.code: 
    blender = callPackage  ../applications/misc/blender {
      pythonPackages = python35Packages;
      stdenv = gcc6Stdenv;
    };
  
    bluefish = callPackage ../applications/editors/bluefish {
  