upgrade to php 5

Hello, I am trying to upgrade the php from 4 to php 5, and configuring it with, ./configure --with-mysql=/usr/local/mysql-max-4.0.18-sun-solaris2.8-sparc/data --with-apx2=/usr/local/apache2/bin/apxs --with-gd=/usr/local --with-jpeg-dir=/usr/local/lib --with-png-dir=/usr/local/lib --with-zlib-dir=/usr/local/lib since mysql ====> /mysql has been mounted to /usr/local/mysql-max-4.0.18-sun-solaris2.8-sparc/data, compiling it as, /mysql gives the same result. and I keep getting, checking for specified location of the MySQL UNIX socket... no checking for MySQL UNIX socket location... no configure: error: Cannot find MySQL header files under /usr/local/mysql-max-4.0.18-sun-solaris2.8-sparc/data Note that the MySQL client library is not bundled anymore. As far as I see from the discussion groups, it's something common, but there is really no answer that I can find, any help appreciated. Thanks much, Hulya