This function was deprecated by OpenSSL in 0.9.8 but code that uses it
still exists. This change adds an implementation of this function to
decreipt/ to support these programs.
Change-Id: Ie99cd00ff8b0ab2675f2b1c821c3d664b9811f16
Reviewed-on: https://boringssl-review.googlesource.com/7360
Reviewed-by: David Benjamin <davidben@google.com>
