archiver in freebsd images appears to be broken

[nagisa]

Checklist

• I've looked through the issues and pull requests for similar reports

Describe your issue

The toolchain used in the freebsd images appears to be broken. I managed to reduce the test case basically down to just:

$ docker pull ghcr.io/cross-rs/x86_64-unknown-freebsd:0.2.4
$ docker run -it ghcr.io/cross-rs/x86_64-unknown-freebsd:0.2.4 bash
$ echo "int banana(void) { return 0; }" | x86_64-unknown-freebsd12-gcc -xc - -c -o chaenomeles.o
$ x86_64-unknown-freebsd12-gcc-ar cq mango.ar chaenomeles.o; echo $?
x86_64-unknown-freebsd12-gcc-ar: Cannot find plugin 'liblto_plugin.so'
1

This in practice causes crates such as cc fail to package the built objects into an .a in crates’ build.rs scripts.

What target(s) are you cross-compiling for?

i686-unknown-freebsd, x86_64-unknown-freebsd

Which operating system is the host (e.g computer cross is on) running?

• macOS
• Windows
• Linux / BSD
• other OS (specify in description)

What architecture is the host?

• x86_64 / AMD64
• arm32
• arm64 (including Mac M1)

What container engine is cross using?

• docker
• podman
• other container engine (specify in description)

cross version

cross 0.2.4

Example

No response

Additional information / notes

The closest relevant thing I can find on the internet is https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81326. Curiously we are already building the toolchain with --disable-lto flag, so it might be a bug in gcc itself?

[Alexhuszagh]

It works if we use x86_64-unknown-freebsd12-ar rather than x86_64-unknown-freebsd12-gcc-ar, which means this should be fixed if we provide AR_x86_64_unknown_freebsd=x86_64-unknown-freebsd12-ar as an environment variable in the Dockerfile.

@nagisa can you confirm the following works for your cross build:
EDIT: See below.

Cross.toml

[target.x86_64-unknown-freebsd]
dockerfile = "./Dockerfile.x86_64-unknown-freebsd"

And then for Dockerfile.x86_64-unknown-freebsd:

FROM ghcr.io/cross-rs/x86_64-unknown-freebsd:0.2.4
ENV AR_x86_64_unknown_freebsd=x86_64-unknown-freebsd12-ar

[Emilgardis]

or just

[target.x86_64-unknown-freebsd.env]
passthrough = ["AR_x86_64_unknown_freebsd=x86_64-unknown-freebsd12-ar"]

[nagisa]

Aha, curious. This seems like it is potentially an issue cc-rs might be interested in in the first place, given its preference towards the -gcc-ar suffix.

https://github.com/rust-lang/cc-rs/blob/2d5cc704dfafad16c873e386244181118cb5e4d1/src/lib.rs#L2623-L2638

and this is a very recent change too (rust-lang/cc-rs#735).

But otherwise yeah setting the environment variable does work.

[Alexhuszagh]

This is also broken for solaris. It might be a good idea to provide AR_$target for all non-glibc/musl images since this might affect people with locked cc-rs versions and prior to a new cc-rs release.