Answer written by Stig Bakken and Martin Jansen.
If you just want to make a simple extension that does not follow
the PEAR coding standards, put it
in pear/PECL/ extname (that is where extensions from
php-src/ext/extname will be moved). If you want to write an extension
following PEAR's function/class naming, put it in pear/Foo_Bar or
whatever the right name is.