anchor.diff:        export PYSISRC=${pysisrc}
         export PATH=$PATH:${binSearchPath}
         export OMPI_MCA_rmaps_base_oversubscribe=1
  -
         echo $PYSISRC
  -
         ${if fullTest
             then "pytest -v tests --disable-warnings"
             else "pytest -v --pyargs pysisyphus.tests --disable-warnings"
         }
       '';
   
  -    postInstall = ''
  +    postInstall = if lib.lists.all (x: x == null) [ gaussian openmolcas orca psi4 xtb multiwfn jmol ]
  +      then "" else ''
         mkdir -p $out/share/pysisyphus
         cp ${pysisrc} $out/share/pysisyphus/pysisrc
         for exe in $out/bin/*; do
  
positive.code:  autograd, dask, distributed, h5py, jinja2, matplotlib, numpy, natsort, pytest, pyyaml, rmsd, scipy,
   sympy, scikitlearn, qcengine, ase, xtb-python, openbabel-bindings,
   # Runtime dependencies
   runtimeShell, jmol, multiwfn, xtb, openmolcas, pyscf, psi4, wfoverlap, nwchem, orca ? null ,
   turbomole ? null, gaussian ? null, gamess-us ? null, cfour ? null, molpro ? null,
   # Test dependencies
   openssh,
  
negative.code:         name = "pysisrc";
        };
  
    binSearchPath = with lib; makeSearchPath "bin" ([ ]
      ++ lists.optional (jmol != null) jmol
      ++ lists.optional (multiwfn != null) multiwfn
      ++ lists.optional (xtb != null) xtb
      ++ lists.optional (openmolcas != null) openmolcas
      ++ lists.optional (pyscf != null) pyscf
      ++ lists.optional (psi4 != null) psi4
      ++ lists.optional (wfoverlap != null) wfoverlap
      ++ lists.optional (nwchem != null) nwchem
      ++ lists.optional (orca != null) orca
      ++ lists.optional (turbomole != null) turbomole
      ++ lists.optional (gaussian != null) gaussian
      ++ lists.optional (cfour != null) cfour
  