on that note, I had hard time using this fix in my embassy project because examples from esp-rs are building their own core and alloc to turn on emulated atomics
```
rustflags = [
# ...
  "--cfg", "target_has_atomic_load_store",
# ...

[unstable]
build-std = ["alloc", "core"]
```

this was fetching compiler-builtins from crates.io no matter what I did - I even ended up having local build of rustc that had those f32 symbols but no atomics and project's core with atomics but no float symbols