anchor.diff:    ];
   
     nativeBuildInputs = [ perl groff cmake ninja python ];
  -  buildInputs = [ libxml2 libffi ncurses zlib ]
  -    ++ stdenv.lib.optional stdenv.isDarwin libcxxabi;
  +  buildInputs = [ libxml2 libffi ncurses zlib ];
   
     # hacky fix: created binaries need to be run before installation
     preBuild = ''
  
positive.code:     "-DLLVM_ENABLE_RTTI=ON"
    ] ++ stdenv.lib.optional enableSharedLibraries
      "-DBUILD_SHARED_LIBS=ON"
      ++ stdenv.lib.optional (!isDarwin)
      "-DLLVM_BINUTILS_INCDIR=${binutils}/include"
      ++ stdenv.lib.optionals ( isDarwin) [
      "-DLLVM_ENABLE_LIBCXX=ON"
      "-DCAN_TARGET_i386=false"
    ];
  
    doCheck = true;
  
  
negative.code: , compiler-rt_src
  , libcxxabi
  , debugVersion ? false
  , enableSharedLibraries ? true
  }:
  
  let
  