Sometimes, using the pecl installer is not an option.
   This could be because you're behind a firewall, or it could be because the
   extension you want to install is not available as a PECL compatible
   package, such as unreleased extensions from SVN.  If you need to build such
   an extension, you can use the lower-level build tools to perform the build
   manually.
  
   The phpize command is used to prepare the build
   environment for a PHP extension.  In the following sample, the sources for
   an extension are in a directory named extname:
  
$ cd extname $ phpize $ ./configure $ make # make install
   A successful install will have created extname.so and put it 
   into the PHP 
   extensions directory.  You'll need
   to and adjust php.ini and add an extension=extname.so
   line before you can use the extension.
  
   If the system is missing the phpize command, and precompiled
   packages (like RPM's) are used, be sure to also install the appropriate 
   devel version of the PHP package as they often include the 
   phpize command along with the appropriate header files to 
   build PHP and its extensions.
  
Execute phpize --help to display additional usage information.