AT TOP LEVEL:
  //-- declare our thread variables
  static pthread_t worker_cdr_thread;

  AST_MUTEX_DEFINE_STATIC(worker_cdr_lock);
  ast_cond_t worker_cdr_cond;


IN LOAD MODULE:
 //-- Create worker thread to post CDR records
 if (ast_pthread_create(&worker_cdr_thread, NULL, voctel_queue_worker, NULL)) {
     ast_log(LOG_ERROR, "VocTelCDR:  Unable to create CDR worker thread\n");
	
     return -1;
 }

IN voctel_queue_worker:
  //--
  ast_log(LOG_DEBUG, "VocTelCDR: Queue Worker thread has started\n");
   

Try using this stuff:

pthread_attr_t attr;

                pthread_attr_init(&attr);
                pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);

ast_pthread_create(thread, &attr, function, data);