rust-openssl, rather than using Rust's existing error types, exposes the
OpenSSL error queue as the error type in its public callback types.
Supporting a simplified version of ERR_set_error_data is simple enough,
so it's easiest just to add this function.
Unlike OpenSSL's, we don't attempt to support non-string error data. We
also don't try to retain borrowed pointers. If the caller did not pass
ownership, make a copy internally.
Change-Id: I909eebc2867ab1f3b9975546a106ee1f762bf516
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/50625
Reviewed-by: Adam Langley <agl@google.com>
David Benjamin
Adam Langley