build-sys: add rule to pack rootfs
diff --git a/Makefile.am b/Makefile.am
index e847c5d..141c102 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -157,6 +157,11 @@
 testsuite-distclean:
 	-rm -rf testsuite/rootfs
 
+testsuite-pack-rootfs:
+	$(AM_V_GEN) ( cd testsuite && tar -cJf \
+			$(abs_top_srcdir)/testsuite/rootfs.tar.xz \
+			rootfs )
+
 DISTCLEAN_LOCAL_HOOKS += testsuite-distclean
 EXTRA_DIST += testsuite/rootfs.tar.xz