Port allocation and destroy changed. Worker process stop introduced.

src/nxt_port.h

@@ -88,6 +88,7 @@ struct nxt_port_s {
     nxt_pid_t           pid;
 
     nxt_process_type_t  type;
+    nxt_work_t          work;
 };
 
 
@@ -110,6 +111,10 @@ typedef union {
 } nxt_port_data_t;
 
 
+nxt_port_t *nxt_port_new(nxt_port_id_t id, nxt_pid_t pid,
+    nxt_process_type_t type);
+nxt_bool_t nxt_port_release(nxt_port_t *port);
+
 nxt_port_id_t nxt_port_get_next_id(void);
 void nxt_port_reset_next_id(void);