Please bump to dev-php/pecl-memcached-2.2.0. It's declared stable and has been out for a little while now. Reproducible: Always
Please also add php5-6 to the USE_PHP in this package as pecl-memcached-2.2.0 is supported upstream with php-5.6.
This is in the tree *pecl-memcached-2.2.0 (28 Sep 2014) 28 Sep 2014; Ole Markus With <olemarkus@gentoo.org> +pecl-memcached-2.2.0.ebuild: Version bump