anchor.diff:      export OMP_NUM_THREADS=2
     '';
   
  -  postInstall = ''
  -    mkdir -p $out/lib/pkgconfig
  -    cp arpack.pc $out/lib/pkgconfig/
  -  '';
  -
  -
     meta = {
       homepage = "https://github.com/opencollab/arpack-ng";
       description = ''
  
positive.code: 
    cmakeFlags = [
      "-DBUILD_SHARED_LIBS=ON"
      "-DINTERFACE64=${lib.optionalString blas.isILP64 "1"}"
    ];
  
    preCheck = if stdenv.isDarwin then ''
  
negative.code:       problems.
      '';
      license = lib.licenses.bsd3;
      maintainers = with lib.maintainers; [ ttuegel dotlambda ];
      platforms = lib.platforms.unix;
    };
  }
  