mtools: update to 4.0.18-r2 for clang fixes

BUG=chromium:644387
TEST=`emerge-amd64-generic mtools` works w/clang

Change-Id: I33d96b9a8bb37836e062ed0afadaa677dde5776f
Reviewed-on: https://chromium-review.googlesource.com/452160
Commit-Ready: Mike Frysinger <vapier@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
Reviewed-by: Yunlian Jiang <yunlian@chromium.org>
(cherry picked from commit cd57ab041601c8a0335fe38315388220f777527b)
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/overlays/portage-stable/+/1582359
Reviewed-by: Hung-Te Lin <hungte@chromium.org>
Commit-Queue: Hung-Te Lin <hungte@chromium.org>
Tested-by: Hung-Te Lin <hungte@chromium.org>
3 files changed