Use the PTHREAD_COND_WAIT macro to check return value.

src/drivers/cpu/driver_cpu.c

@@ -163,7 +163,7 @@ void *_starpu_cpu_worker(void *arg)
 
                 if (j == NULL) {
 			if (_starpu_worker_can_block(memnode))
-				pthread_cond_wait(&queue->activity_cond, &queue->activity_mutex);
+				PTHREAD_COND_WAIT(&queue->activity_cond, &queue->activity_mutex);
 			_starpu_jobq_unlock(queue);
  			continue;
 		};

src/drivers/cuda/driver_cuda.c

@@ -245,7 +245,7 @@ void *_starpu_cuda_worker(void *arg)
 
 		if (j == NULL) {
 			if (_starpu_worker_can_block(memnode))
-				pthread_cond_wait(&queue->activity_cond, &queue->activity_mutex);
+				PTHREAD_COND_WAIT(&queue->activity_cond, &queue->activity_mutex);
 			_starpu_jobq_unlock(queue);
 			continue;
 		}