Mysqli for PHP in package mysql
Solution 1:
From the description of the package php5-mysql(version 5.3.10-1ubuntu3.2) :
This package provides modules for MySQL database connections directly from PHP scripts. It includes the generic "mysql" module which can be used to connect to all versions of MySQL, an improved "mysqli" module for MySQL version 4.1 or later, and the pdo_mysql module for use with the PHP Data Object extension.
So, the package php5-mysql does contain support for MYSQLi extension.