[php-maint] Bug#654393: an alternative

[Julien Wajsberg]

As an alternative, you could create a specific package, like
php5-mysqlnd, and keep the current package linking to libmysqlclient.
php5-mysqlnd would _not_ have the driver "mysql" (as opposed to "mysqli").

Then we wouldn't break existing installation

When PHP 5.4 will be released, php5-mysqlnd would be a dummy package
depending on php5-mysql.