Import valgrind 3.7.0-r4 ebuild.

Valgrind 3.6 doesn't work on our targets because it doesn't support
glibc 2.15. So switch to valgrind 3.7.0.

BUG=none
TEST=by hand

Change-Id: Id7b65f76d79816508439766a386e1186ae175856
Reviewed-on: https://gerrit.chromium.org/gerrit/29005
Tested-by: Stéphane Marchesin <marcheu@chromium.org>
Reviewed-by: Antoine Labour <piman@chromium.org>
Commit-Ready: Stéphane Marchesin <marcheu@chromium.org>
13 files changed