futility: updater: Fix build failure due to fts.

`fts` in old branches cannot use 64 bit file offset.

BUG=chromium:923934
TEST=emerge-gru vboot_reference

Change-Id: I0184847b19e470c86aac9a7cbb2d7b1f3cbf653d
Reviewed-on: https://chromium-review.googlesource.com/c/1426260
Reviewed-by: Hung-Te Lin <hungte@chromium.org>
Commit-Queue: Hung-Te Lin <hungte@chromium.org>
Tested-by: Hung-Te Lin <hungte@chromium.org>
Trybot-Ready: Hung-Te Lin <hungte@chromium.org>
diff --git a/futility/updater_archive.c b/futility/updater_archive.c
index 1c8030b..814bbc0 100644
--- a/futility/updater_archive.c
+++ b/futility/updater_archive.c
@@ -5,6 +5,8 @@
  *
  * Accessing updater resources from an archive.
  */
+#include "host_common.h"
+#undef __USE_FILE_OFFSET64
 
 #include <assert.h>
 #include <ctype.h>