+Allow ZOOM caching using redis. New ZOOM option "redis" controls it.
+
+RPM: do not build with libmemcached support. The libmemcached library
+on CentOS 5/6 does not work reliably for us (redis to the rescue).
+
+configure: only allow libmemcached version 0.40 or later. That's the version
+on Debian squeeze. We recommend libmemcached version 1.0 or later. If
+that's not an option, consider redis.
+
--- 5.1.3 2014/06/04
Fix dup ZOOM_EVENT_RECV_RECORD events for SRU/Solr YAZ-768