diff --git a/build.rs b/build.rs
index 7fbb466..5f72cca 100644
--- a/build.rs
+++ b/build.rs
@@ -9,6 +9,7 @@ fn build_tramp()
     builder.flag("--std=c99")
 	.flag("-W")
 	.flag("-Wall")
+	.flag_if_supported("-Wextra")
 	.flag("-Werror")
 	.flag("-pedantic")
 	.opt_level(3)