anchor.diff:        runtime = [ SDL ];
         cmakeEnableFlag = "GR_VIDEO_SDL";
       };
  -    # codec2 and gsm support is broken with gr3.9: https://github.com/gnuradio/gnuradio/issues/4278
  -    # gr-vocoder = {
  -      # runtime = [ codec2 gsm ];
  -      # cmakeEnableFlag = "GR_VOCODER";
  -    # };
  +    gr-vocoder = {
  +      runtime = [ codec2 gsm ];
  +      cmakeEnableFlag = "GR_VOCODER";
  +    };
       gr-wavelet = {
         cmakeEnableFlag = "GR_WAVELET";
         runtime = [ gsl libsodium ];
  
positive.code:   } // lib.optionalAttrs (hasFeature "gr-qtgui" features) {
      inherit (libsForQt5) qwt;
    };
  
    postInstall = shared.postInstall
      # This is the only python reference worth removing, if needed.
  
negative.code:     src
      nativeBuildInputs
      buildInputs
      disallowedReferences
      stripDebugList
      doCheck
  