<!-- Thanks for filing a 🐛 bug report 😄! -->

[bgu5678]

Problem

The file format of the output binary of cargo build -Zbuild-std=core,alloc is not recognized.

Steps

1. Clone https://github.com/toku-sa-n/cargo_bug
2. git checkout with_rlibc
3. make

This causes the error: ld: target/cargo_settings/debug/librust_bug.a: error adding symbols: file format not recognized

Possible Solution(s)

Sorry, but I have no idea.

Notes

Output of cargo version:cargo 1.45.0-nightly (cb06cb269 2020-05-08)

rlibc is deprecated, but with compiler_builtins (which is the replacement of rlibc) , cargo build -Zbuild-std=core,alloc itself fails with the error: multiple rlib candidates for compiler_builtins found. rust-lang/wg-cargo-std-aware#53 seems to be related.

Building without compiler_builtins will cause another linker error: undefined reference to 'memcpy'.

Related issue: rust-osdev/cargo-xbuild#69

最初由 @toku-sa-n 在 rust-lang/cargo#8239 发布