anchor.diff:      sha256 = "3c9dcb686217b2efe0e988e90b95777c4591e3335e259e01a94af87e0bf01809";
     };
   
  -  nativeBuildInputs = [ autogen autoconf automake gettext libtool pkg-config py3 unzip which ];
  +  # when building on darwin we need dawin.cctools to provide the correct libtool
  +  # as libwally-core detects the host as darwin and tries to add the -static
  +  # option to libtool, also we have to add the modified gsed package.
  +  nativeBuildInputs = [ autogen autoconf automake gettext pkg-config py3 unzip which ] 
  +    ++ lib.optionals stdenv.isDarwin [ darwin.cctools ] ++ [ libtool ];
   
     buildInputs = [ gmp libsodium sqlite zlib ];
   
  -  postPatch = ''
  +  # this causes some python trouble on a darwin host so we skip this step.
  +  # also we have to tell libwally-core to use sed instead of gsed.
  +  postPatch = if !stdenv.isDarwin then ''
       patchShebangs \
         tools/generate-wire.py \
         tools/update-mocks.sh \
         tools/mockup.sh \
         devtools/sql-rewrite.py
  +  '' else ''
  +    substituteInPlace external/libwally-core/tools/autogen.sh --replace gsed sed && \
  +    substituteInPlace external/libwally-core/configure.ac --replace gsed sed
     '';
   
     configureFlags = [ "--disable-developer" "--disable-valgrind" ];
  
positive.code: { lib
  , stdenv
  , fetchurl
  , autoconf
  , automake
  
negative.code:     homepage = "https://github.com/ElementsProject/lightning";
      maintainers = with maintainers; [ jb55 prusnak ];
      license = licenses.mit;
      platforms = platforms.linux ++ [ "x86_64-darwin" ];
    };
  }
  