Description

Yet another patch to fix the broken canary builds. Adding fallback imports to conda._vendor.toolz for all tlz imports.

This is necessary because of how conda build builds packages:

1. conda build generates the necessary build environment (which contains the new conda dependencies, e.g. toolz)
2. conda build generates a build_env_setup.sh script where at the very end, it runs something like:

   ...
   eval "$('path/to/python' -m conda shell.bash hook)"
   conda activate <ENV1>
   conda activate --stack <ENV2>
   

   this occurs in conda_build.build._write_sh_activation_text.
3. conda build changes directories to the working directory (in this case a shallow clone of our conda repo)
4. conda build runs the build_env_setup.sh from our working directory so when path/to/python -m conda ... is invoked the CWD (working directory) is added to Python's search path, and hence the conda source code is loaded even though all we are attempting to do is bootstrap the build environment.

The correct fix is to change the path/to/python -m conda ... command to path/to/conda ... but this is a chicken/egg problem, so we need to keep this PR's fix in place until conda-build is updated and released.

Xref: #11698

Checklist - did you ...

• Add a file to the news directory (using the template) for the next release's release notes?
• Add / update necessary tests?
• Add / update outdated documentation?