This is to transition BoringSSL's Windows build from Yasm to NASM. This
change itself is a no-op for now, but a later change to the BoringSSL
recipes will add a pair of standalone builders here. Then I'll get the
change I have lying around for Chromium moving.
Bug: chromium:766721
Change-Id: I4dca1c299f93bc5c01695983fe0478490c472deb
Reviewed-on: https://boringssl-review.googlesource.com/29324
Reviewed-by: Steven Valdez <svaldez@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>