anchor.diff:      buildInputs = [
         gau2grid
         libxc
  -      mkl
  +      blas
  +      lapack
         dkh_
         pcmsolver_
         libefp
  
positive.code:         --subst-var out
      '';
  
      doCheck = false;
      checkPhase = ''
        runHook preCheck
        ctest -j $NIX_BUILD_CORES
      '';
  
      doInstallCheck = true;
      installCheckPhase = ''
        export OMP_NUM_THREADS=2
  
negative.code: { lib, buildPythonPackage, buildPackages, makeWrapper, fetchFromGitHub, fetchurl, pkg-config
  , writeTextFile, cmake, perl, gfortran, python, pybind11, qcelemental, qcengine, numpy, pylibefp
  , deepdiff, blas, lapack, gau2grid, libxc, dkh, dftd3, pcmsolver, libefp, chemps2, hdf5, hdf5-cpp
  , pytest, mpfr, gmpxx, eigen, boost
  } :
  
  