&reftitle.install;

`--enable-intl` will enable the extension while compiling PHP.

If your ICU is installed to a non-standard directory then you might want to specify its location in `LD_LIBRARY_PATH` environment variable so that dynamic linker can find it:

    $ export LD_LIBRARY_PATH=/opt/icu/lib

Otherwise, if PHP and ICU are installed to their default locations, then the additional options to `configure` are not needed.