anchor.diff: -{ stdenv, fetchFromGitHub, writeText, makeWrapper
  +{ stdenv
  +, fetchFromGitHub
  +, makeWrapper
  +, writeText
   # Dependencies documented @ https://gnuradio.org/doc/doxygen/build_guide.html
   # => core dependencies
  -, cmake, pkgconfig, git, boost, cppunit, fftw
  +, cmake
  +, pkgconfig
  +, git
  +, boost
  +, cppunit
  +, fftw
   # => python wrappers
   # May be able to upgrade to swig3
  -, python, swig2, numpy, scipy, matplotlib
  +, python
  +, swig2
  +, numpy
  +, scipy
  +, matplotlib
   # => grc - the gnu radio companion
  -, Mako, cheetah, pygtk # Note: GR is migrating to Mako. Cheetah should be removed for GR3.8
  +, Mako
  +, cheetah
  +, pygtk # Note: GR is migrating to Mako. Cheetah should be removed for GR3.8
   # => gr-wavelet: collection of wavelet blocks
   , gsl
   # => gr-qtgui: the Qt-based GUI
  -, qt4, qwt, pyqt4
  +, qt4
  +, qwt
  +, pyqt4
   # => gr-wxgui: the Wx-based GUI
  -, wxPython, lxml
  +, wxPython
  +, lxml
   # => gr-audio: audio subsystems (system/OS dependent)
   , alsaLib   # linux   'audio-alsa'
   , CoreAudio # darwin  'audio-osx'
  
positive.code:   };
  
    nativeBuildInputs = [
      cmake pkgconfig git makeWrapper cppunit orc
    ];
  
    buildInputs = [
      boost fftw python swig2 lxml qt4
      qwt SDL libusb1 uhd gsl
    ] ++ stdenv.lib.optionals stdenv.isLinux  [ alsaLib   ]
      ++ stdenv.lib.optionals stdenv.isDarwin [ CoreAudio ];
  
    propagatedBuildInputs = [
      Mako cheetah numpy scipy matplotlib pyqt4 pygtk wxPython pyopengl
    ];
  
    NIX_LDFLAGS = "-lpthread";
  
negative.code: # => gr-video-sdl: PAL and NTSC display
  , SDL
  # Other
  , libusb1
  , orc
  , pyopengl
  }:
  
  stdenv.mkDerivation rec {
  