Why do you get a "Fatal error: Call to undefined function: stripos()" when editing Joomla! 1.5.7 Articles from the frontend when using PHP 4?

Problem: MarkCII reported that for PHP 4 environments, Joomla! gives this error message when Articles are submitted from the frontend:

"Fatal error: Call to undefined function: stripos() in /libraries/joomla/environment/uri.php on line 675"

Articles are still successfully posted.

Possible resolutions:

• Add this to the end of /libraries/joomla/utilities/compat/php50x.php

if(!function_exists('stripos')) {
 function stripos($haystack, $needle, $offset = 0) {
  return strpos(strtolower($haystack), strtolower($needle), $offset);
 }
}

• OR - Upgrade to PHP 5. PHP 4 end of life was August 8, 2008. There will not be any more PHP 4 releases, even for security.

• OR - Ignore until Joomla! 1.5.8 since the Article is saved correctly.