Using "standard" env variables in the "Pipeline" env variable section

We want to use `$BUILDKITE_BUILD_ID` in one of the global env variables.

Example:
```sh
my_unique_temp_directory=/tmp/$BUILDKITE_BUILD_ID
cache_directory=$my_unique_temp_directory/cache
```

Right now reading this https://buildkite.com/docs/pipelines/environment-variables#environment-variable-precedence - it seems like it's impossible as the standard env variables are evaluated last.

This makes me re-define env variables at the beginning of every step that needs to use those locations.

Is there any way to work around it?