minimal-bootstrap.gnumake-musl: fix build

GNU Make's release tarball contains pregenerated Autotools files and
depends on archive mtimes to keep them newer than their inputs.

The Mes-built gnutar used by gnumake-musl does not preserve those mtimes.
That can make configure.ac and m4 files appear newer than aclocal.m4 or
Makefile.in, causing make to try to run aclocal/automake during the
minimal bootstrap build.

Use gnutar-musl here, which is already documented as preserving mtimes for
pregenerated files.

Assisted-by: OpenAI Codex (GPT-5.5)

pkgs/os-specific/linux/minimal-bootstrap/default.nix

@@ -184,6 +184,9 @@ lib.makeScope
           tinycc = tinycc-musl;
           gawk = gawk-mes;
           gnumakeBoot = gnumake;
+          # GNU Make's release tarball relies on preserved mtimes for
+          # pregenerated Autotools files.
+          gnutar = gnutar-musl;
         };
 
         gnumake-static = callPackage ./gnumake/static.nix {