- Add OpenSSL 1.1.1 to the header/library version lists.
- Detect OpenSSL 1.1.1 library using its function ERR_clear_last_mark,
which was added in that version.
Prior to this change an erroneous header/library mismatch was caused by
lack of OpenSSL 1.1.1 detection. I tested using openssl-1.1.1-pre1.