E_ALL Compliance: install.php assumes port set

On first install (and subsequent check), install.php generates the following notices:

Notice: Undefined index: port in c:\program files\apache group\apache\htdocs\drupalhead\install.php on line 113

Notice: Undefined index: port in c:\program files\apache group\apache\htdocs\drupalhead\install.php on line 135

In each case, either in install_verify_settings() or install_change_settings(), following

    $url = parse_url($db_url);

the offending line assumes port is set

  $db_port = urldecode($url['port']);

whereas parse_url() will only set those parts it finds. For clarity and E_ALL compliance we can change to

  $db_port = isset($url['port']) ? urldecode($url['port']) : NULL;

The attached patch does this for both lines. Mark.