Re: Rust support

[Joshua Branson]

Awesome!!! Keep up the cool work!

On Mon, Dec 25, 2017, at 8:19 PM, David Michael wrote:
> Hi,
> 
> I've been poking at cross-compiling Rust projects for Hurd on and off
> for a couple of weeks, and I thought I'd upload what I have now for
> comments.  A new snapshot of my silly Hurd distro is available at
> https://github.com/dm0-/gnuxc updated with the Rust reimplementation
> of librsvg, so there is an example user of this.
> 
> The distro commit contains a patch[1] against the current Rust release
> (1.22.1) which can be used to build std libraries for Hurd with your
> Linux-based system's existing rustc.  I've also pushed the patch
> against master[2].  See the RPM spec file[3] for the commands to build
> the std libraries and a target spec JSON file.
> 
> Since Rust doesn't have a default path, the environment variable
> RUST_TARGET_PATH must be set to the directory containing the JSON spec
> file.  With that and the rlib files installed to
> /usr/lib/rustlib/i686-pc-gnu/lib, Rust projects can be built for Hurd
> with "cargo --target=i686-pc-gnu build".  The command "rustc
> --codegen=ar=i686-pc-gnu-gcc-ar --codegen=linker=i686-pc-gnu-gcc
> --target=i686-pc-gnu" will directly compile Rust files without cargo.
> 
> Note that projects will likely depend on libc, which will need to be
> patched with the same changes used to build std.  The librsvg
> package[4] has an example of how to do this with vendored crates, but
> other projects may require you to set up a local registry and patch it
> there.
> 
> The current implementation reuses the Linux code with some additional
> conditional blocks, but I think it may be better to start a new OS
> port for Hurd.  Otherwise, it may turn into whack-a-mole, tweaking
> constants when new packages encounter bugs, or adding more conditions
> as the Linux implementation is developed.  I'll continue to work on
> this (at an as yet undetermined pace) to hopefully make it
> upstreamable, but any help or feedback from the Hurd side would be
> appreciated to prevent me from doing something dumb.  In case anyone
> else does want to work on this before I get to it, I'd suggest
> prioritizing porting the libc crate--the sooner it has a release with
> Hurd support, the sooner every other project depending on a specific
> libc version will be able to update to build out of the box.
> 
> Thanks.
> 
> David
> 
> [1] 
> https://github.com/dm0-/gnuxc/blob/master/patches/rust-1.22.1-hurd-port.patch
> [2] https://github.com/dm0-/rust/commits/hurd
> [3] https://github.com/dm0-/gnuxc/blob/master/specs/gnuxc-rust.spec#L39
> [4] https://github.com/dm0-/gnuxc/blob/master/make.pkg.d/librsvg.mk#L8
>