MB-6352 Define _POSIX_PTHREAD_SEMANTICS
MB-6352 Define _POSIX_PTHREAD_SEMANTICS

Change-Id: Ia607dccece47bad41c3794a5f331c98579289f51
Reviewed-on: http://review.couchbase.org/19954
Reviewed-by: Trond Norbye <60edd2ef23891a753f231b0c6f161dc634079a93@gmail.com>
Tested-by: Trond Norbye <60edd2ef23891a753f231b0c6f161dc634079a93@gmail.com>

cloudrain21/memcached-1,owendCB/memcached,daverigby/memcached,daverigby/kv_engine,abhinavdangeti/memcached,cloudrain21/memcached-1,cloudrain21/memcached-1,daverigby/kv_engine,daverigby/memcached,owendCB/memcached,abhinavdangeti/memcached,abhinavdangeti/memcached,mrkwse/memcached,abhinavdangeti/memcached,jimwwalker/memcached,mrkwse/memcached,cloudrain21/memcached-1,jimwwalker/memcached,abhinavdangeti/memcached,couchbase/memcached,daverigby/memcached,jimwwalker/memcached,daverigby/kv_engine,mrkwse/memcached,couchbase/memcached,owendCB/memcached,daverigby/kv_engine,mrkwse/memcached,owendCB/memcached,couchbase/memcached,couchbase/memcached,daverigby/memcached