anchor.diff:  , enableManpages ? false
   , enableSharedLibraries ? true
   , enableWasm ? true
  +, enablePFM ? !stdenv.isDarwin
   }:
   
   let
  
positive.code: , python
  , libffi
  , libbfd
  , libxml2
  , ncurses
  , version
  
negative.code:   nativeBuildInputs = [ cmake python ]
      ++ stdenv.lib.optional enableManpages python.pkgs.sphinx;
  
    buildInputs = [ libxml2 libffi ]
      ++ stdenv.lib.optional enablePFM libpfm; # exegesis
  
    propagatedBuildInputs = [ ncurses zlib ];
  
  