anchor.diff:  { stdenv, fetchFromGitHub, python, gfortran, openblasCompat
   , fftw, libint2, libxc, mpi, gsl, scalapack, openssh, makeWrapper
  -, libxsmm, which
  +, libxsmm, spglib, which
   , optAVX ? false
   } :
   
  
positive.code:     LD         = mpif90
      AR         = ar -r
      DFLAGS     = -D__FFTW3 -D__LIBXC -D__LIBINT -D__parallel -D__SCALAPACK \
                   -D__MPI_VERSION=3 -D__F2008 -D__LIBXSMM \
                   -D__MAX_CONTR=4
  
      FCFLAGS    = \$(DFLAGS) -O2 -ffree-form -ffree-line-length-none \
  
negative.code:   };
  
    nativeBuildInputs = [ python which openssh makeWrapper ];
    buildInputs = [ gfortran fftw gsl libint2 libxc libxsmm  spglib openblasCompat mpi scalapack ];
  
    makeFlags = [
      "ARCH=${arch}"
  