usleep is guarded by feature macro insanity. Use nanosleep which looks to be less unfriendly. Change-Id: I75cb2284f26cdedabb19871610761ec7440b6ad3 Reviewed-on: https://boringssl-review.googlesource.com/7710 Reviewed-by: Emily Stark (Dunn) <estark@google.com> Reviewed-by: David Benjamin <davidben@google.com>kris/onging/CECPQ3_patch15