Credit to the Ubuntu people for resolving this issue already - since memcached 1.2.8 is currently pencilled in for Karmic Koala release of Ubuntu later this year - but I can't wait that long so I updated my own memcached, it was pretty easy so here are the steps in case anyone else wants to do the same.
- download memcached from http://www.danga.com/memcached/download.bml
- check you have the dependencies you need. The only thing I didn't have was the libraries for libevent, which you can install through aptitude with aptitude install libevent-dev
- compile as you usually would: configure/make/make install
The final step is to get memcached running - I actually did aptitude remove memcached to get rid of my old version and stop myself from being confused later. Then to start it from command line I used:
/usr/local/bin/memcached -m 64 -p 11211 -u nobody -l 0.0.0.0
The above worked for me and allowed me to use the functionality available in the newer library (specifically I was looking to use the cas (compare and swap) functionality in the new PHP memcached extension) - it probably works on other distros too but I didn't test it, if it works for you or if you have anything to add then please leave a comment!