From e796054f9ee7722a9b473de8de737a443bbd1112 Mon Sep 17 00:00:00 2001
From: Lokathor <zefria@gmail.com>
Date: Fri, 6 Sep 2019 18:02:11 -0600
Subject: [PATCH] Update build.rs

---
 library/compiler-builtins/build.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/library/compiler-builtins/build.rs b/library/compiler-builtins/build.rs
index 5cdabf95987e..b520b62477ed 100644
--- a/library/compiler-builtins/build.rs
+++ b/library/compiler-builtins/build.rs
@@ -9,7 +9,7 @@ fn main() {
     println!("cargo:compiler-rt={}", cwd.join("compiler-rt").display());
 
     // Activate libm's unstable features to make full use of Nightly.
-    println!("rustc-cfg=libm/unstable");
+    println!("cargo:rustc-cfg=feature=\"unstable\"");
 
     // Emscripten's runtime includes all the builtins
     if target.contains("emscripten") {