Linux stdenv update: pass gnugrep to cc-wrapper

pkgs/stdenv/linux/default.nix

···
   # the bootstrap.  In all stages, we build an stdenv and the package
   # set that can be built with that stdenv.
   stageFun =
-    {gccPlain, glibc, binutils, coreutils, name, overrides ? (pkgs: {}), extraBuildInputs ? []}:
+    {gccPlain, glibc, binutils, coreutils, gnugrep, name, overrides ? (pkgs: {}), extraBuildInputs ? []}:
 
     let
 
···
           cc = gccPlain;
           isGNU = true;
           libc = glibc;
-          inherit binutils coreutils;
+          inherit binutils coreutils gnugrep;
           name = name;
           stdenv = stage0.stdenv;
         };
···
     glibc = null;
     binutils = null;
     coreutils = null;
+    gnugrep = null;
     name = null;
 
     overrides = pkgs: {
···
     inherit (stage0.pkgs) glibc;
     binutils = bootstrapTools;
     coreutils = bootstrapTools;
+    gnugrep = bootstrapTools;
     name = "bootstrap-gcc-wrapper";
 
     # Rebuild binutils to use from stage2 onwards.
···
     inherit (stage1.pkgs) glibc;
     binutils = stage1.pkgs.binutils;
     coreutils = bootstrapTools;
+    gnugrep = bootstrapTools;
     name = "bootstrap-gcc-wrapper";
 
     overrides = pkgs: {
···
     gccPlain = bootstrapTools;
     inherit (stage2.pkgs) glibc binutils;
     coreutils = bootstrapTools;
+    gnugrep = bootstrapTools;
     name = "bootstrap-gcc-wrapper";
 
     overrides = pkgs: rec {
···
   # Construct a fourth stdenv that uses the new GCC.  But coreutils is
   # still from the bootstrap tools.
   stage4 = stageFun {
-    inherit (stage3.pkgs) gccPlain glibc binutils;
+    inherit (stage3.pkgs) gccPlain glibc binutils gnugrep;
     coreutils = bootstrapTools;
     name = "";
 
···
         isGNU = true;
         cc = stage4.stdenv.cc.cc;
         libc = stage4.pkgs.glibc;
-        inherit (stage4.pkgs) binutils coreutils;
+        inherit (stage4.pkgs) binutils coreutils gnugrep;
         name = "";
         stdenv = stage4.stdenv;
         shell = stage4.pkgs.bash + "/bin/bash";