Do not deny warnings by default.

libc currently denies all warnings by default. This commit denies
warnings only when libc is built in CI.

1 files changed, 5 insertions, 1 deletions

diff --git a/build.rs b/build.rs
index efc95b6627..d9d23ca2ac 100644
--- a/build.rs
+++ b/build.rs
@@ -7,7 +7,6 @@ fn main() {
         rustc_minor_version().expect("Failed to get rustc version");
     let rustc_dep_of_std = env::var("CARGO_FEATURE_RUSTC_DEP_OF_STD").is_ok();
     let align_cargo_feature = env::var("CARGO_FEATURE_ALIGN").is_ok();
-    #[allow(unused)]
     let libc_ci = env::var("LIBC_CI").is_ok();
 
     if env::var("CARGO_FEATURE_USE_STD").is_ok() {
@@ -28,6 +27,11 @@ fn main() {
         Some(_) | None => println!("cargo:rustc-cfg=freebsd11"),
     }
 
+    // On CI: deny all warnings
+    if libc_ci {
+        println!("cargo:rustc-cfg=libc_deny_warnings");
+    }
+
     // Rust >= 1.15 supports private module use:
     if rustc_minor_ver >= 15 || rustc_dep_of_std {
         println!("cargo:rustc-cfg=libc_priv_mod_use");