nixos: use nativeBuildInputs in make- iso9660-image and system-tarball

The tools used to create iso9660 images and tarballs are independent of
the platform of the closure contained within.

+1 -1
nixos/lib/make-iso9660-image.nix
···
stdenv.mkDerivation {
name = isoName;
builder = ./make-iso9660-image.sh;
-
buildInputs = [ xorriso syslinux zstd libossp_uuid ];
+
nativeBuildInputs = [ xorriso syslinux zstd libossp_uuid ];
inherit isoName bootable bootImage compressImage volumeID efiBootImage efiBootable isohybridMbrImage usbBootable;
+1 -1
nixos/lib/make-system-tarball.nix
···
stdenv.mkDerivation {
name = "tarball";
builder = ./make-system-tarball.sh;
-
buildInputs = extraInputs;
+
nativeBuildInputs = extraInputs;
inherit fileName extraArgs extraCommands compressCommand;