I am running lighttpd with PHP5-FCGI and ZendOptimizer. When starting lighttpd, the following error occurs:

hosting# /usr/local/etc/rc.d/lighttpd restart
Performing sanity check on lighttpd configuration:
Syntax OK
Stopping lighttpd.
Waiting for PIDS: 7946.
Starting lighttpd.
hosting# Failed loading /usr/local/lib/php/20060613/ZendExtensionManager.so:  Shared object "libm.so.4" not found, required by "ZendExtensionManager.so"
Failed loading /usr/local/lib/php/20060613/ZendExtensionManager.so:  Shared object "libm.so.4" not found, required by "ZendExtensionManager.so"
Failed loading /usr/local/lib/php/20060613/ZendExtensionManager.so:  Shared object "libm.so.4" not found, required by "ZendExtensionManager.so"
Failed loading /usr/local/lib/php/20060613/ZendExtensionManager.so:  Shared object "libm.so.4" not found, required by "ZendExtensionManager.so"

And ZendOptimizer is not started.

Fix: 

It seems that libm.so.5 is able to provide Zend everything he needs:

# ln -s /lib/libm.so.5 /lib/libm.so.4

My opinion is that pkg-message should be changed to show the above message.
How-To-Repeat: 1) Install lighttpd:
# pkg_add -r lighttpd

2) Install php5 and extensions
# pkg_add -r php5
# pkg_add -r php5-extensions

3) Enable PHP5-FCGI in Lighttpd
Edit /usr/local/etc/lighttpd.conf like it says on
http://trac.lighttpd.net/trac/wiki/TutorialLighttpdAndPHP#Configuration

4) Install ZendOptimizer
# cd /usr/ports/devel/ZendOptimizer
# make install
Edit php.ini as it says in pkg-message.

5) Start lighttpd
# /usr/local/etc/rc.d/lighttpd forcestart