ossl_md5_sha1_ctrl
return ossl_md5_sha1_ctrl(EVP_MD_CTX_get0_md_data(ctx), cmd, mslen, ms);
return ossl_md5_sha1_ctrl(ctx, EVP_CTRL_SSL3_MASTER_SECRET,
int ossl_md5_sha1_ctrl(MD5_SHA1_CTX *mctx, int cmd, int mslen, void *ms);