This adds experimental support for using OCSP with libcurl that is built
against BoringSSL. This needs small modifications to libcurl to allow
CURLOPT_SSL_VERIFYSTATUS to be used to call
SSL_enable_ocsp_stapling(connssl->handle) in ossl_connect_step1().
Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>