anchor.diff:    # build to use PYQT5_SIP_DIR consistently.
     postPatch = ''
        substituteInPlace cmake/FindPyQt5.py \
  -       --replace 'pyqtcfg.pyqt_sip_dir' '"${python3Packages.pyqt5}/share/sip/PyQt5"'
  +       --replace 'sip_dir = cfg.default_sip_dir' 'sip_dir = "${python3Packages.pyqt5}/share/sip/PyQt5"'
      '';
   
     cmakeFlags = [ "-DCMAKE_SKIP_BUILD_RPATH=OFF"
  
positive.code:     inherit python3Packages;
    };
  
    buildInputs = [ openssl proj geos xlibsWrapper sqlite gsl qwt
      fcgi libspatialindex libspatialite postgresql txt2tags libzip hdf5 netcdf
      qtbase qtwebkit qtsensors qca-qt5 qtkeychain qscintilla qtserialport qtxmlpatterns] ++
      (stdenv.lib.optional withGrass grass) ++ pythonBuildInputs;
  
negative.code: { stdenv, lib, fetchFromGitHub, cmake, ninja, flex, bison, proj, geos, xlibsWrapper, sqlite, gsl
  , qwt, fcgi, python3Packages, libspatialindex, libspatialite, postgresql
  , txt2tags, openssl, libzip, hdf5, netcdf, exiv2
  , qtbase, qtwebkit, qtsensors, qca-qt5, qtkeychain, qscintilla, qtserialport, qtxmlpatterns
  , withGrass ? true, grass
  }:
  