pkgs/stdenv/linux/default.nix: restore dropped gcc-wrapper

7459a40 `stdenv-bootstrap: force using new libc from stage2` overrode
`gcc-wrapper`. 91fa7657 `stdenv: revert gcc hack` dod not restore the initial
value.

As a result attempt to build glibc-2.35 fails early on perl as:

   ld: cannot find -lnsl: No such file or directory
   collect2: error: ld returned 1 exit status
   I can't compile the test program.
   (The supplied flags or libraries might be incorrect.)

The change restores `gcc-wrapper` as it was before 7459a40.

pkgs/stdenv/linux/default.nix

@@ -230,7 +230,7 @@ in
     overrides = self: super: {
       inherit (prevStage)
         ccWrapperStdenv
-        coreutils gnugrep
+        gcc-unwrapped coreutils gnugrep
         perl gnum4 bison;
       dejagnu = super.dejagnu.overrideAttrs (a: { doCheck = false; } );