This extension may be installed using the bundled version as of PHP 5.3.0, or as a PECL extension as of PHP 5.2.0. In other words, there are two methods to install the intl extension.
Alternatively, --enable-intl will enable the bundled version while compiling PHP.
If your ICU is installed to a non-standard directory then you might want to
specify its location in
environment variable so that dynamic linker can find it:
Otherwise, if PHP and ICU are installed to their default locations, then the additional options to `configure' are not needed.