Problem: dead code in options.hpp

Solution: remove unused zap_ipc_creds boolean variable

src/options.hpp

@@ -166,7 +166,6 @@ namespace zmq
 
         // IPC accept() filters
 #       if defined ZMQ_HAVE_SO_PEERCRED || defined ZMQ_HAVE_LOCAL_PEERCRED
-        bool zap_ipc_creds;
         typedef std::set <uid_t> ipc_uid_accept_filters_t;
         ipc_uid_accept_filters_t ipc_uid_accept_filters;
         typedef std::set <gid_t> ipc_gid_accept_filters_t;