gnu: glibc-stripped: Empty 'native-inputs' and 'propagated-inputs'.

These would needlessly pull in linux-libre-headers when running
"guix build bootstrap-tarballs --target=i586-pc-gnu".

* gnu/packages/make-bootstrap.scm (%glibc-stripped)[native-inputs]
[propagated-inputs]: New fields.

gnu/packages/make-bootstrap.scm

@@ -382,6 +382,8 @@ (define (%glibc-stripped)
                                 (parameterize ((%current-target-system #f))
                                   (cross-libc target)))
                                glibc)))))
+      (native-inputs '())
+      (propagated-inputs '())
 
       ;; Only one output.
       (outputs '("out")))))