Set login options
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_LOGIN_OPTIONS, char *options);
Pass a char * as parameter, which should be pointing to the zero terminated options string to use for the transfer.
For more information about the login options please see RFC2384, RFC5092 and IETF draft draft-earhart-url-smtp-00.txt
CURLOPT_LOGIN_OPTIONS(3) can be used to set protocol specific login options, such as the preferred authentication mechanism via "AUTH=NTLM" or "AUTH=*", and should be used in conjunction with the CURLOPT_USERNAME(3) option.
Only IMAP, POP3 and SMTP support login options.
Added in 7.34.0
Returns CURLE_OK if the option is supported, CURLE_UNKNOWN_OPTION if not, or CURLE_OUT_OF_MEMORY if there was insufficient heap space.