diff --git a/candle-flash-attn/build.rs b/candle-flash-attn/build.rs
index 18694524f3..e6cefb92c4 100644
--- a/candle-flash-attn/build.rs
+++ b/candle-flash-attn/build.rs
@@ -73,7 +73,7 @@ fn main() -> Result<()> {
     };
 
     let kernels = KERNEL_FILES.iter().collect();
-    let builder = bindgen_cuda::Builder::default()
+    let mut builder = bindgen_cuda::Builder::default()
         .kernel_paths(kernels)
         .out_dir(build_dir.clone())
         .arg("-std=c++17")