We can actually use modules now.

Change-Id: I0bd8abaf4e3318069f93fa17e89b4804d03944eb
Reviewed-on: https://boringssl-review.googlesource.com/c/33205
Commit-Queue: David Benjamin <davidben@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
Reviewed-by: Adam Langley <agl@google.com>