Add CF_DPCPP_ENABLED

[ZzEeKkAa]

Checklist

• Added a news entry
• Regenerated schema JSON if schema altered (python conda_smithy/schema.py)

Addresses #2129 issue. Will be resolve after merging this PR and updating https://github.com/conda-forge/conda-forge-pinning-feedstock/blob/main/recipe/conda_build_config.yaml

[isuruf]

I'm not sure why this is needed. Can you explain?

[ZzEeKkAa]

@isuruf as I described in #2129, I'm trying to add dpcpp compiler option to pytorch build. However I'm facing problems with zip_keys, so I'm trying to do something like this:
https://github.com/conda-forge/conda-forge-pinning-feedstock/pull/6686/files

I was using cuda as an example. I guess reason for the CF_(CUDA|DPCPP)_ENABLED is to disable generation of compiler specific options if they are not in use.

I'm open to other solutions of the original issue, but this is the only solution I can see.