diff --git a/build.rs b/build.rs
index 7562129..5bedb53 100644
--- a/build.rs
+++ b/build.rs
@@ -85,7 +85,7 @@ fn main() {
         .include("include")
         .files(sources)
         .file("src/errno.c")
-        .flag("-w")
+        .extra_warnings(false)
         .compile("wasm32-unknown-unknown-openbsd-libc");
 
     println!(