is wp-config.php update save?

I must insert a certain line into the wp config,
when the wordpress core updates, will these settings
then still be there, or will everything be overwritten?

this is what i have to add into the wp-config.php and
should be retained among future updates:

//ssl patch begin
  $domain = 'www.mydomain.com';
  if($_SERVER['HTTP_X_FORWARDED_HOST']=="ssl.webpack.de") {
        // mit SSL-oxy
      define('WP_SITEURL', 'https://ssl.webpack.de/' . $domain);
      define('WP_HOME', 'https://ssl.webpack.de/' . $domain);
      $_SERVER['HTTPS'] = 'on';
      $_SERVER['REQUEST_URI'] = '/' . $domain . $_SERVER['REQUEST_URI'];
  } else {
        // Ohne SSLroxy
      define('WP_SITEURL', 'http://' . $domain);
      define('WP_HOME', 'http://' . $domain);
  }
//ssl patch end

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