When I try to install php 5.3 stable from source on Ubuntu (downloading compressed installation file from http://www.php.net/downloads.php) and I run ./configure
I get this error:
configure: error: xml2-config not found. Please check your libxml2 installation.
All you need to do instal install package libxml2-dev for example:
sudo apt-get install libxml2-dev
On CentOS/RHEL:
sudo yum install libxml2-devel