anchor.diff:      else null;
   
     passthru =
  -    { inherit langC langCC langObjC langObjCpp langAda langFortran langVhdl langGo version; isGNU = true; };
  +    { inherit langC langCC langAda langFortran langVhdl langGo version; isGNU = true; };
   
     inherit enableParallelBuilding enableMultilib;
   
  
positive.code:     ++ (optionals javaAwtGtk ([ gtk libart_lgpl ] ++ xlibs))
      ++ (optionals (cross != null) [binutilsCross])
      ++ (optionals langAda [gnatboot])
      ++ (optionals langVhdl [gnat])
  
      # The builder relies on GNU sed (for instance, Darwin's `sed' fails with
      # "-i may not be used with stdin"), and `stdenvNative' doesn't provide it.
      ++ (optional stdenv.isDarwin gnused)
      ++ (optional stdenv.isDarwin binutils)
      ;
  
    NIX_LDFLAGS = stdenv.lib.optionalString  stdenv.isSunOS "-lm -ldl";
  
  
negative.code: 
  # LTO needs libelf and zlib.
  assert libelf != null -> zlib != null;
  
  # The go frontend is written in c++
  assert langGo -> langCC;
  