GH-146475: Block Apple Clang for building JIT stencils

[savannahostrowski]

This PR carries forward a patch that stalled out in #146478, which has been open for over a month with no follow up from the original author (hadn't signed the CLA otherwise, I would have just pushed to their PR and merged there).

• Issue: JIT might accidentally use Apple LLVM 21 on macOS #146475

[StanFromIreland]

@savannahostrowski Triage: are you planning to backport or can we close #146475?

[miss-islington-app]

Thanks @savannahostrowski for the PR 🌮🎉.. I'm working now to backport this PR to: 3.13.
🐍🍒⛏🤖 I'm not a witch! I'm not a witch!

[miss-islington-app]

Thanks @savannahostrowski for the PR 🌮🎉.. I'm working now to backport this PR to: 3.14.
🐍🍒⛏🤖

[miss-islington-app]

Sorry, @savannahostrowski, I could not cleanly backport this to 3.13 due to a conflict.
Please backport using cherry_picker on command line.

cherry_picker c0e064003954142b4ba820dfe149f893227c4f11 3.13

[savannahostrowski]

Yeah, I think we probably do want to backport this. I'll do that and then close out the issue.

[miss-islington-app]

Sorry, @savannahostrowski, I could not cleanly backport this to 3.14 due to a conflict.
Please backport using cherry_picker on command line.

cherry_picker c0e064003954142b4ba820dfe149f893227c4f11 3.14

[bedevere-app]

GH-149339 is a backport of this pull request to the 3.14 branch.

[bedevere-app]

GH-149340 is a backport of this pull request to the 3.13 branch.

[bedevere-bot]

⚠️⚠️⚠️ Buildbot failure ⚠️⚠️⚠️

Hi! The buildbot AMD64 Debian root 3.14 (tier-1) has failed when building commit c55cce2.

What do you need to do:

1. Don't panic.
2. Check the buildbot page in the devguide if you don't know what the buildbots are or how they work.
3. Go to the page of the buildbot that failed (https://buildbot.python.org/#/builders/1742/builds/1191) and take a look at the build logs.
4. Check if the failure is related to this commit (c55cce2) or if it is a false positive.
5. If the failure is related to this commit, please, reflect that on the issue and make a new Pull Request with a fix.

You can take a look at the buildbot page here:

https://buildbot.python.org/#/builders/1742/builds/1191

Summary of the results of the build (if available):

==

Click to see traceback logs

Traceback (most recent call last):
File "/root/buildarea/3.14.angelico-debian-amd64/build/Lib/test/support/__init__.py", line 859, in gc_collect
gc.collect()
ResourceWarning: unclosed file <_io.FileIO name=13 mode='wb' closefd=True>