Gentoo users: emerge does not compile dev-lang/php with --enable-xmlreader by default. To enable this option, add the flag xmlreader to your USE variable and recompile php.
The XMLReader extension was initially a PECL extension for PHP 5. It was later moved to the PHP source (bundled) as of PHP 5.1.0, and later enabled by default as of PHP 5.1.2.
This extension is enabled by default. It may be disabled by using the following option at compile time: --disable-xmlreader
Gentoo users: emerge does not compile dev-lang/php with --enable-xmlreader by default. To enable this option, add the flag xmlreader to your USE variable and recompile php.
If you are having trouble loading this extension (perhaps with a log message like 'Undefined symbol "dom_node_class_entry"'), make sure that you have xmlreader.so listed AFTER dom.so in php.ini.