anchor.diff:  
     buildInputs = [
       boost
  -    catch
  +    catch2
       inchi
       eigen
       cairo
  
positive.code: , fetchzip
  , cmake
  , boost
  , catch
  , inchi
  , cairo
  , eigen
  
negative.code:   '';
  
    cmakeFlags = [
      "-DCATCH_DIR=${catch2}/include/catch2"
      "-DINCHI_LIBRARY=${inchi}/lib/libinchi.so"
      "-DINCHI_LIBRARIES=${inchi}/lib/libinchi.so"
      "-DINCHI_INCLUDE_DIR=${inchi}/include/inchi"
  