options=

static VALUE
ossl_sslctx_set_options(VALUE self, VALUE options)
{
    SSL_CTX *ctx;

    rb_check_frozen(self);
    GetSSLCTX(self, ctx);

    SSL_CTX_clear_options(ctx, SSL_CTX_get_options(ctx));

    if (NIL_P(options)) {
        SSL_CTX_set_options(ctx, SSL_OP_ALL);
    } else {
        SSL_CTX_set_options(ctx, NUM2ULONG(options));
    }

    return self;
}