Fix broken non-buffer_labels build
diff --git a/src/engine.rs b/src/engine.rs
index 76d7524..1a0e9f8 100644
--- a/src/engine.rs
+++ b/src/engine.rs
@@ -717,6 +717,7 @@
         let props = BufferProperties {
             size: rounded_size,
             usages: usage,
+            #[cfg(feature = "buffer_labels")]
             name: name,
         };
         if let Some(buf_vec) = self.bufs.get_mut(&props) {