etherboot: use gzip -n

to not include current timestamp in results
to allow for reproducible builds.

See https://reproducible-builds.org/ for why this matters

Signed-off-by: Bernhard M. Wiedemann <bwiedemann@suse.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>

tools/firmware/etherboot/Makefile

@@ -31,7 +31,7 @@ $T:
 	if ! $(FETCHER) _$T $(IPXE_TARBALL_URL); then \
 		$(GIT) clone $(IPXE_GIT_URL) $D.git; \
 		(cd $D.git && $(GIT) archive --format=tar --prefix=$D/ \
-		$(IPXE_GIT_TAG) | gzip >../_$T); \
+		$(IPXE_GIT_TAG) | gzip -n >../_$T); \
 		rm -rf $D.git; \
 	fi
 	mv _$T $T

tools/firmware/etherboot/README

@@ -15,7 +15,7 @@ as on 25th September 2008):
 
  git clone git://git.etherboot.org/scm/gpxe.git
  cd gpxe
- git archive --format=tar --prefix=gpxe/ c24bc349ead939d90b5784dbff3cd9fdb9d83ba8 | gzip >../gpxe-git-snapshot.tar.gz
+ git archive --format=tar --prefix=gpxe/ c24bc349ead939d90b5784dbff3cd9fdb9d83ba8 | gzip -n >../gpxe-git-snapshot.tar.gz
 
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