anchor.diff:      sha256 = "sha256-SL9PcT18vFvykCv4VRXxXtlcDAcybmwEImnnKXMciFQ=";
     };
   
  -  # Normally, igraph wants us to call bootstrap.sh, which will call
  -  # tools/getversion.sh. Instead, we're going to put the version directly
  -  # where igraph wants, and then let autoreconfHook do the rest of the
  -  # bootstrap. ~ C.
     postPatch = ''
       echo "${version}" > IGRAPH_VERSION
     '' + lib.optionalString stdenv.isAarch64 ''
  
positive.code:     gmp
      lapack
      libxml2
      suitesparse
    ];
  
    cmakeFlags = [
  
negative.code:     "-DIGRAPH_USE_INTERNAL_GLPK=OFF"
      "-DIGRAPH_USE_INTERNAL_CXSPARSE=OFF"
      "-DIGRAPH_USE_INTERNAL_GMP=OFF"
      "-DIGRAPH_USE_INTERNAL_PLFIT=OFF"
      "-DIGRAPH_GLPK_SUPPORT=ON"
      "-DIGRAPH_GRAPHML_SUPPORT=ON"
      "-DIGRAPH_OPENMP_SUPPORT=ON"
      "-DIGRAPH_ENABLE_LTO=AUTO"
      "-DIGRAPH_ENABLE_TLS=ON"
      "-DBUILD_SHARED_LIBS=ON"
  