syntax error, unexpected '{'

/**
 * Returns TRUE if 'menu_links_features_export_render' is in the callstack.
 */
function _menu_token_is_called_from_features() {
...
      if (version_compare(PHP_VERSION, '5.3.6', '>=') {  <----------------
        $callstack = debug_backtrace(DEBUG_BACKTRACE_IGNORE_ARGS);
      }
...
  return !$called;
}