/*
 * call-seq:
 *   easy.dns_cache_timeout = fixnum or nil           => fixnum or nil
 *
 * Set the dns cache timeout in seconds. Name resolves will be kept in
 * memory for this number of seconds. Set to zero (0) to completely disable
 * caching, or set to nil (or -1) to make the cached entries remain forever.
 * By default, libcurl caches this info for 60 seconds.
 */
static VALUE ruby_curl_easy_dns_cache_timeout_set(VALUE self, VALUE dns_cache_timeout) {