(Based on Piotr Sikora's change:
https://boringssl-review.googlesource.com/#/c/1361)

Change-Id: I7b62b81f4e4ef3064eee1b39334dc2e50d17f163
Reviewed-on: https://boringssl-review.googlesource.com/1641
Reviewed-by: Adam Langley <agl@google.com>

BUG=396787

Change-Id: I72ddb0ec3c71dbc70054403163930cbbde4b6009
Reviewed-on: https://boringssl-review.googlesource.com/1581
Reviewed-by: Adam Langley <agl@google.com>

Initial fork from f2d678e6e8 (1.0.2 beta).

(This change contains substantial changes from the original and
effectively starts a new history.)