Memcached/yrmcds client extension for PHP5 Formula was removed
Last versions were
php53-yrmcds requires the following formula to be installed:
autoconf 2.69 Automatic configure script builder

Recent formula history

Mike McQuaid Deprecate tap.
Baptiste Fontaine php53-yrmcds: audit fixes
Andy Blyler php53-yrmcds: convert from sha1 to sha256
Andy Blyler fix style issues
Lucas Fix brew audit warning

Formula code at GitHub