After getting PHP 5.0.5 to compile on my Solaris 9 server, I got the following error when doing the make install:
ld.so.1: php: fatal: relocation error: file /u01/packages/src/php-5.0.5/sapi/cli/php: symbol xmlRelaxNGCleanupTypes: referenced symbol not found
make: *** [install-pear-installer] Error 137
make: *** [install-pear] Error 2
Turns out that the Sun XML packages are stomping all over the xml2 package from http://xmlsoft.org/. Simply removing the following two packages allowed the make install to complete.
# pkgrm SUNWlxml
# pkgrm SUNWlxmlx