I don’t think it can be done without building an own error handler, but technically, that is the one global change you’re looking for.
Modified example from the manual:
function myErrorHandler($errno, $errstr, $errfile, $errline)
{
// you'd have to import or set up the connection here
mysql_query("INSERT INTO error_log (number, string, file, line) ".
"VALUES .....");
/* Don't execute PHP internal error handler */
return true;
}
then
// set to the user defined error handler
$old_error_handler = set_error_handler("myErrorHandler");