Making sqlite shared extension in windows distribution of php-5.1

We need to make sqlite into a shared extension (php_sqlite.dll) on
Windows for the php-5.1 release. This is because PDO will be changed to
be a shared extension too to accommodate for the possibility to release
independent PECL versions of it between the regular PHP releases and
ext/sqlite depends on it.

In practice this means that Windows users will have to insert a single
line into their php.ini file to enable sqlite2 support.

Edin