Re: Compiling Rust, Rust toolchains for openbsd 7.2

On Mon, Nov 07, 2022 at 01:47:28AM +0200, flipchan wrote:
> Hey everyone,
>
> I have a "building instance" that cross compiles a rust code repository to
> darwin, linux and some other platforms. I want to add support for compiling
> rust code to openbsd 7.2. However, Openbsd does not have an official rust
> toolchain. List of supported systems can be found here:
> https://doc.rust-lang.org/nightly/rustc/platform-support.html
>
>
> Does anyone have a rust-toolchain work around for compiling rust code on a
> linux box to be able to produce a binary executable for a amd64 openbsd 7.2
> server?

Rust toolchain is built natively on all supported platforms (amd64, i386, arm64,
sparc64, powerpc64, riscv64).

In order to cross-compile it from Linux, you first need C/C++ crosscompiler to
target OpenBSD.

Most of the architectures (but not all) are based on LLVM toolchain (clang,
libc++, libc++abi…), and most of the patches to properly support OpenBSD are
upstreamed. So I advice you to first try to cross-compile simple C and C++
programs from Linux to OpenBSD to ensure that your C toolchain is working.

You will need standard libraries and objects from
https://cdn.openbsd.org/pub/OpenBSD/7.2/ (at least base72.tgz and comp72.tgz)

Once done, you should be able to cross-compile Rust using standard Rust tools.
See https://doc.rust-lang.org/nightly/rustc/platform-support/openbsd.html

As reminder, OpenBSD versions are major version for each release: 7.1 and 7.2
are both major versions (with potential breaking changes between versions). Do
not assume that a binary targeting 7.2 will be able to run on 7.3. OpenBSD isn't
like Linux.

Thanks.
--
Sebastien Marie