If we need an extension, we can implement it in-library.
Change-Id: I0eac5affcd8e7252b998b6c86ed2068234134b08
Reviewed-on: https://boringssl-review.googlesource.com/1051
Reviewed-by: Adam Langley <agl@google.com>
Initial fork from f2d678e6e89b6508147086610e985d4e8416e867 (1.0.2 beta).
(This change contains substantial changes from the original and
effectively starts a new history.)