--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lang/rust/patch-rust.patch	Wed Oct 23 07:10:36 2019 +0200
@@ -0,0 +1,23 @@
+$OpenBSD: patch-src_bootstrap_lib_rs,v 1.24 2019/09/29 08:23:17 semarie Exp $
+let us compilation choice to be honored.
+https://github.com/rust-lang/rust/issues/39900
+Index: src/bootstrap/lib.rs
+--- src/bootstrap/lib.rs.orig
++++ src/bootstrap/lib.rs
+@@ -104,7 +104,7 @@
+ //! also check out the `src/bootstrap/README.md` file for more information.
+ 
+ // NO-RUSTC-WRAPPER
+-#![deny(warnings, rust_2018_idioms, unused_lifetimes)]
++#![deny(rust_2018_idioms, unused_lifetimes)]
+ 
+ #![feature(core_intrinsics)]
+ #![feature(drain_filter)]
+@@ -768,7 +768,6 @@ impl Build {
+         // cc-rs because the build scripts will determine that for themselves.
+         let mut base = self.cc[&target].args().iter()
+                            .map(|s| s.to_string_lossy().into_owned())
+-                           .filter(|s| !s.starts_with("-O") && !s.starts_with("/O"))
+                            .collect::<Vec<String>>();
+ 
+         // If we're compiling on macOS then we add a few unconditional flags