$OpenBSD: patch-src_bootstrap_lib_rs,v 1.15 2018/09/16 16:35:27 landry 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
@@ -742,7 +742,6 @@ 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<_>>();
 
         // If we're compiling on macOS then we add a few unconditional flags
