$OpenBSD: patch-src_libunwind_build_rs,v 1.4 2019/09/29 08:23:17 semarie Exp $
some archs are still using estdc++ and not c++
https://github.com/rust-lang/rust/pull/63595

Index: src/libunwind/build.rs
--- src/libunwind/build.rs.orig
+++ src/libunwind/build.rs
@@ -25,7 +25,11 @@ fn main() {
     } else if target.contains("netbsd") {
         println!("cargo:rustc-link-lib=gcc_s");
     } else if target.contains("openbsd") {
-        println!("cargo:rustc-link-lib=c++abi");
+        if target.contains("sparc64") {
+            println!("cargo:rustc-link-lib=gcc");
+        } else {
+            println!("cargo:rustc-link-lib=c++abi");
+        }
     } else if target.contains("solaris") {
         println!("cargo:rustc-link-lib=gcc_s");
     } else if target.contains("dragonfly") {
