Add the SSL_OP_NO_RENEGOTIATION option to 1.1.0
This is based on a heavily modified version of commit
db0f35dda by Todd
Short from the master branch.
We are adding this because it used to be possible to disable reneg using
the flag SSL3_FLAGS_NO_RENEGOTIATE_CIPHERS in 1.0.2. This is no longer
possible because of the opacity work.
A point to note about this is that if an application built against new
1.1.0 headers (that know about the new option SSL_OP_NO_RENEGOTIATION
option) is run using an older version of 1.1.0 (that doesn't know about
the option) then the option will be accepted but nothing will happen, i.e.
renegotiation will not be prevented. There's probably not much we can do
about that.
Fixes #4739
Reviewed-by: Ben Kaduk <kaduk@mit.edu>
(Merged from https://github.com/openssl/openssl/pull/4901)