anchor.diff:    # the wrappers:
     preFixup = ''
       gappsWrapperArgs+=(
  -      --prefix LD_LIBRARY_PATH ":" "$out/lib/darktable"
  +      --prefix LD_LIBRARY_PATH ":" "$out/lib/darktable:${ocl-icd}/lib"
       )
     '';
   
  
positive.code: , ilmbase, gtk3, intltool, lcms2, lensfun, libX11, libexif, libgphoto2, libjpeg
  , libpng, librsvg, libtiff, openexr, osm-gps-map, pkgconfig, sqlite, libxslt
  , openjpeg, lua, pugixml, colord, colord-gtk, libwebp, libsecret, gnome3
  }:
  
  stdenv.mkDerivation rec {
  
negative.code:     libgphoto2 libjpeg libpng librsvg libtiff openexr sqlite libxslt
      libsoup graphicsmagick json-glib openjpeg lua pugixml
      colord colord-gtk libwebp libsecret gnome3.adwaita-icon-theme
      osm-gps-map ocl-icd
    ];
      
    cmakeFlags = [
      "-DBUILD_USERMANUAL=False"
    ];
  