Fix MLX C++20 errors

[metascroy]

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[pytorch-bot]

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✅ You can merge normally! (1 Unrelated Failure)

As of commit 6cb4ab0 with merge base 1074d73 ():

BROKEN TRUNK - The following job failed but were present on the merge base:

👉 Rebase onto the `viable/strict` branch to avoid these failures

• pull / android / run-emulator (gh) (trunk failure)
  adb: failed to install android-test-debug-androidTest.apk: cmd: Can't find service: package

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