These are not actual extensions. They are part of the PHP core and cannot be left out of a PHP binary with compilation options.
These extensions are bundled with PHP.
Riferimento VII, Funzioni Matematiche BCMath a precisione arbitraria
Riferimento XXIV, Database (dbm-style) Abstraction Layer Functions
Riferimento LXXXII, Mohawk Software Session Handler Functions
Riferimento LXXXIX, Ncurses Terminal Screen Control Functions
Riferimento CVIII, Funzioni per le espressioni regolari (Perl compatibili)
Riferimento LXXXI, Microsoft SQL Server and Sybase Functions (PDO_DBLIB)
Riferimento CXXXI, Funzioni per i semafori, la memoria condivisa ed IPC
In order to compile these extensions, external libraries will be needed.
These extensions are available from PECL. More PECL extensions exist but they are not documented in the PHP manual yet.