Disable '-D warnings` in CI. (#105)

Disable '-D warnings` in CI to avoid `unexpected_cfgs` failures in a way
that doesn't break Rust 1.34.

.github/actions/install-rust/main.js

@@ -18,9 +18,12 @@ child_process.execFileSync('rustup', ['default', toolchain]);
 
 // Deny warnings on CI to keep our code warning-free as it lands in-tree. Don't
 // do this on nightly though since there's a fair amount of warning churn there.
-if (!toolchain.startsWith('nightly')) {
-  set_env("RUSTFLAGS", "-D warnings");
-}
+//
+// Disable this for now to avoid `unexpected_cfgs` in a way that works with
+// Rust 1.34.
+//if (!toolchain.startsWith('nightly')) {
+//  set_env("RUSTFLAGS", "-D warnings");
+//}
 
 // Save disk space by avoiding incremental compilation, and also we don't use
 // any caching so incremental wouldn't help anyway.

src/lib.rs

@@ -16,6 +16,7 @@
     )
 )]
 #![cfg_attr(not(feature = "std"), no_std)]
+
 #[cfg(not(feature = "std"))]
 extern crate alloc;
 #[cfg(feature = "std")]