diff --git a/build.rs b/build.rs
index 84c37e5..e934539 100644
--- a/build.rs
+++ b/build.rs
@@ -1,10 +1,11 @@
+#[cfg(feature = "builtin-lua")]
 extern crate gcc;
 
-use std::env;
-
 fn main() {
     #[cfg(feature = "builtin-lua")]
     {
+        use std::env;
+
         let mut config = gcc::Config::new();
 
         let target_os = env::var("CARGO_CFG_TARGET_OS");