The pecl (pear) provider assumes all extensions are of the form package_name.so, which is not always the case.
Also it has no support for extensions which must be loaded by the zend extension loader.
I've fixed this in my branch: https://github.com/leth/cookbooks/tree/pecl-zend
I'm pretty new with ruby, so any coding style/idiom suggestions would be welcome.
P.S. Pull request incoming.