tl;dr: minimally failing example

Description

In a project I'm working on, we're using tokio's unstable features. Those features require opt-in through an environmnent variable. This environment variable can be set in the file .cargo/config.toml, which is what we do. Unfortunately, dist build seems to ignore this configuration. As a result, the compilation step during dist build fails.

What I've tried

• Running RUSTFLAGS="--cfg tokio_unstable" dist build¹ works fine.
• I cannot find anything applicable to this situation in the dist book.
• I was unable to identify similar issues here on github.

Questions

1. Do you consider this a bug or missing feature, or am I miss- or even abusing dist?
2. Is there a maintainable workaround? I feel uncomfortable monkey-patching the release.yml to jam this environment variable in there every time I run dist init.
3. Do you need or want any additional information?