anchor.diff:  # This was written partly based on https://github.com/EliasOenal/TNT,
   # and the patches were also taken from there.
   
  -{ stdenv, fetchurl, gmp, mpfr, libmpc, isl_0_11, cloog_0_18_0
  +{ stdenv, fetchurl, gmp, mpfr, libmpc, isl
   , zlib, libelf, texinfo, bison, flex
   , optimizeForSize ? false
   }:
   let
  -    gcc_version = "6.3.0";
  +    gcc_version = "6.4.0";
       binutils_version = "2.28";
       newlib_version = "2.5.0.20170421";
       
  
positive.code:     sourceRoot = ".";
      
      nativeBuildInputs = [ texinfo bison flex ];
      buildInputs = [ gmp mpfr libmpc isl_0_11 cloog_0_18_0 zlib libelf ];
      
      hardeningDisable = [ "format" ];
      
  
negative.code:             sha256 = "6297433ee120b11b4b0a1c8f3512d7d73501753142ab9e2daa13c5a3edd32a72";
          })
          (fetchurl {
              url = "mirror://gnu/gcc/gcc-${gcc_version}/gcc-${gcc_version}.tar.xz";
              sha256 = "850bf21eafdfe5cd5f6827148184c08c4a0852a37ccf36ce69855334d2c914d4";
          })
          (fetchurl {
              url = "ftp://sourceware.org/pub/newlib/newlib-${newlib_version}.tar.gz";
  