cdylib doesn't include unmangled symbols from dependencies even when explicitly re-exported.

[sadmac7000]

I tried this code:

in foo.rs:

#[no_mangle]
pub unsafe extern "C" fn foo() {}

in bar.rs:

extern crate foo;

pub use foo::*;

On the console:

$ rustc --crate-type=rlib foo.rs
$ rustc --crate-type=cdylib bar.rs -L.
$ readelf -s libbar.so |grep foo

I expected to see this happen:
readelf should show my unmangled symbol.

Instead, this happened:
the symbol is missing from the crate.

Meta

rustc --version --verbose:

rustc 1.48.0
binary: rustc
commit-hash: unknown
commit-date: unknown
host: x86_64-unknown-linux-gnu
release: 1.48.0
LLVM version: 11.0

[gheoan]

Is this a duplicate of #50007?

@rustbot modify labels: +A-linkage, +T-compiler

[tmandry]

Looks like it is (other issues mentioning cdylib explicitly have been closed as duplicates of it), thanks. Closing as a duplicate of #50007.