anchor.diff:  
     nativeBuildInputs = [ python3 which openssh makeWrapper pkg-config ];
     buildInputs = [
  -    elpa
       gfortran
       fftw
       gsl
  
positive.code:     scalapack
      blas
      lapack
    ];
  
    propagatedBuildInputs = [ mpi ];
    propagatedUserEnvPkgs = [ mpi ];
  
negative.code:     AR         = ar -r
      DFLAGS     = -D__FFTW3 -D__LIBXC -D__LIBINT -D__parallel -D__SCALAPACK \
                   -D__MPI_VERSION=3 -D__F2008 -D__LIBXSMM -D__SPGLIB \
                   -D__MAX_CONTR=4 -D__LIBVORI ${lib.optionalString enableElpa "-D__ELPA"}
      CFLAGS    = -fopenmp
      FCFLAGS    = \$(DFLAGS) -O2 -ffree-form -ffree-line-length-none \
                   -ftree-vectorize -funroll-loops -msse2 \
                   -std=f2008 \
                   -fopenmp -ftree-vectorize -funroll-loops \
                   -I${libxc}/include -I${libxsmm}/include \
                   -I${libint}/include ${lib.optionalString enableElpa "$(pkg-config --variable=fcflags elpa)"}
      LIBS       = -lfftw3 -lfftw3_threads \
                   -lscalapack -lblas -llapack \
                   -lxcf03 -lxc -lxsmmf -lxsmm -lsymspg \
                   -lint2 -lstdc++ -lvori \
                   -lgomp -lpthread -lm \
                   -fopenmp ${lib.optionalString enableElpa "$(pkg-config --libs elpa)"}
      LDFLAGS    = \$(FCFLAGS) \$(LIBS)
      EOF
    '';
  