You're right. PHP in Cool Stack does not include this library. It is obviously not possible to include all of the PHP libraries out there. What we've done is to include a 'config.sh' script in the source directory that tells you how we've built it and you can simply edit it to include whatever library you want. Download the library and run the script and you should have a good, optimized version for Solaris that meets your needs.
The 'config.sh' script resides in each source directory - please download the src tar file.
Shanti