`create_feedstocks`: bug with `conda_build_config.yaml`?

### Solution to issue cannot be found in the documentation.

- [x] I checked the documentation.

### Issue

I think recipes with a `conda_build_config.yaml` file are tripping the CI pipeline here. I had to patch the submission to define `c_stdlib` manually, even though the `.ci_support` file should have that already. Maybe we are missing a flag somewhere to prevent CBC shadowing the .ci_support definitions.

- Erroring workflow: https://github.com/conda-forge/admin-requests/actions/runs/26031776880
- Fix: https://github.com/conda-forge/staged-recipes/commit/15a51e772966bd283189bf5a1e8dc123eb5def89
- Successful workflow: https://github.com/conda-forge/admin-requests/actions/runs/26035435124/job/76532128789

### Installed packages

```shell
N/A
```

### Environment info

```shell
N/A
```