Zig bundles its own private copies of glibc or musl for each platofrm, crt.o, system headers, cross-linkers, and clang. They've done a lot of work to replicate cross-build toolkits for each target:

https://andrewkelley.me/post/zig-cc-powerful-drop-in-replace...

As a Rust user I'm super jealous of that, because Rust's "rustup target add" gives a false illusion of being able to cross-compile, but it can only build object files/static libraries, and if you ask for anything more, Rust just spits a big linker error and you're on your own.

Wonder if Rust should pursue this as a feature as well - might be hard to promise this as a fully fledged feature when Cranelift comes into the picture though. Still it could be possible to ship a linker that can handle cross-compiling like Zig and compile C code with LLVM irregardless of the Rust backend.

Either way, hope Zig and Rust continue to inspire each other a bit!

I've only ever cross compiled no_std rust, but as long as I'm writing a rust app with C deps (and not a C app with rust deps) everything has just worked for me.

What caused the linker errors for you?

(My issues with a rust lib for a C app were based around how rustc didn't want to include panicking code from core, even with a panic handler defined)

Rust depends on the operating system already having a cross-linker and sysroot for the target platform. You probably have them already installed.

On a "clean" OS, you get:

• Panics from sys crates using the pkg_config crate, because the target sysroot is missing. It can auto-detect available sysroot on some Linux platforms, but on others you need to fiddle with env vars.

• Screen full of linker errors, because the linker for the host OS doesn't know what to do with the target OS's object files. It's less terrible if you enable a semi-secret option for bundled lld, but it's too buggy to use on some platforms.

Cross-compilation from one Linux flavor to another Linux flavor is reasonably easy with some distros. But anything more adventurous like Mac -> Linux just falls apart and you need to spend a whole day copy-pasting configs and installing bitrotting 3rd party Homebrew formulas from random people on the Internet.

Rust's tooling is usually excellent, but cross-compilation feels half-finished. The Rust's own side of it is fine (cross-compiles object files like a champ, has cross-libstd), but anything not written by the Rust project is left as "not our problem".