anchor.diff:      };
   
       overrides = pkgs: {
  -      inherit (stage1Pkgs) glibc linux-headers;
  +      inherit (stage1Pkgs) glibc linux-headers_3-18 linux-headers;
         inherit (stage2Pkgs) m4 gnum4 which;
         inherit (stage3Pkgs) gcc6 gcc xz zlib attr acl gmp coreutils binutils
           gpm ncurses readline bash nghttp2_lib cryptodevHeaders gettext bison flex
  -        openssl c-ares curl libsigsegv pcre findutils diffutils gnused gnugrep
  -        gawk gnutar gnutar_1-29 gzip brotli brotli_0-5-2 bzip2 gnumake gnupatch
  -        pkgconf pkgconfig patchelf;
  +        openssl_1-0-2 openssl c-ares curl libsigsegv pcre findutils diffutils
  +        gnused gnugrep gawk gnutar gnutar_1-29 gzip brotli brotli_0-5-2 bzip2
  +        gnumake gnupatch pkgconf pkgconfig patchelf;
       };
     });
   
  
positive.code:       };
  
        overrides = pkgs: (lib.mapAttrs (n: _: throw "stage1Pkgs is missing package definition for `${n}`") pkgs) // {
          inherit (pkgs) stdenv glibc linux-headers;
  
          gcc6 = lib.makeOverridable (import ../../build-support/cc-wrapper) {
            nativeTools = false;
  
negative.code:       };
  
        overrides = pkgs: (lib.mapAttrs (n: _: throw "stage2Pkgs is missing package definition for `${n}`") pkgs) // {
          inherit (stage1Pkgs) glibc linux-headers_3-18 linux-headers;
          inherit (pkgs) stdenv gnum4 m4 which gettext elfutils gcc isl;
          bzip2 = pkgs.bzip2.override { static = true; shared = false; };
          libelf = pkgs.libelf.override { static = true; shared = false; };
          gmp = pkgs.gmp.override { stdenv = pkgs.makeStaticLibraries pkgs.stdenv; };
          isl_0-16 = pkgs.isl_0-16.override { stdenv = pkgs.makeStaticLibraries pkgs.stdenv; };
          libmpc = pkgs.libmpc.override { stdenv = pkgs.makeStaticLibraries pkgs.stdenv; };
          mpfr = pkgs.mpfr.override { stdenv = pkgs.makeStaticLibraries pkgs.stdenv; };
          xz = pkgs.xz.override { stdenv = pkgs.makeStaticLibraries pkgs.stdenv; };
  