rustc needs parameter for soname (or ld flags in general)

[metux]

rustc currently doesn't add, and doesn't allow specifying the library soname.
Thus, ld cannot differenciate between binary versions, which makes it extremley hard to have multiple versions coexist (requires horrible LD_LIBRARY_PATH games), and therefore causes bad headaches for distro packaging.

Actually, it doesn't even allow passing any linker flags at all.

[cuviper]

You can use rustc -Clink-arg=-Wl,-soname=foo.so.1.

But as I mentioned in #43186, I don't think one should do this without actually ensuring the ABI stability that this implies. It's not there at all for Rust APIs -- rust-lang/rfcs#600 -- and even if it were it would probably still take some effort by the library author to do it right.

It could make sense for a cdylib, if you do make sure to keep that ABI stable.

[codyps]

In the context of cargo, that could be RUSTFLAGS="-Clink-arg=-Wl,-soname=foo.so.1" cargo build, but it seems likely that this will pass the -soname arg in more places than desirable (to dependencies, non-cdylib crates in the package, etc).

For supporting cdylibs, it may make sense to add some cargo support. Alternately, one could use something like patchelf to set the soname after the fact.

[Mark-Simulacrum]

This feels like this is perhaps a Cargo issue, since I think -Clink-arg on Rust's side is sufficient based on discussion here. This may need an RFC, though.