anchor.diff:  
       overrides = pkgs: {
         inherit (stage1Pkgs) glibc linux-headers;
  -      inherit (stage2Pkgs) m4 gnum4 which gettext;
  +      inherit (stage2Pkgs) m4 gnum4 which;
         inherit (stage3Pkgs) gcc xz zlib attr acl gmp coreutils binutils
  -        gpm ncurses readline bash libnghttp2 cryptodevHeaders
  +        gpm ncurses readline bash libnghttp2 cryptodevHeaders gettext
           openssl c-ares curl libsigsegv pcre findutils diffutils gnused gnugrep
           gawk gnutar gzip bzip2 gnumake gnupatch pkgconf pkgconfig patchelf;
       };
  
positive.code:   };
  
    # This is the second package set using the final glibc and bootstrap tools.
    # This stage is used for building the final gcc.
    # Propagates stage1 glibc and linux-headers.
    stage2Pkgs = allPackages rec {
      inherit targetSystem hostSystem config;
  
negative.code:       overrides = pkgs: (lib.mapAttrs (n: _: throw "stage3Pkgs is missing package definition for `${n}`") pkgs) // {
          pkgs = stage3Pkgs;
          inherit (stage1Pkgs) glibc linux-headers;
          inherit (stage2Pkgs) m4 gnum4 which;
          inherit (pkgs) stdenv xz zlib attr acl gmp coreutils binutils
            gpm ncurses readline bash libnghttp2 cryptodevHeaders gettext
            openssl c-ares curl libsigsegv pcre findutils diffutils gnused gnugrep
            gawk gnutar gzip bzip2 gnumake gnupatch pkgconf pkgconfig patchelf;
  
  