Make CMake builds independent of checkout name

[rascani]

Summary

Remove the requirement that the repository directory itself be named executorch. Generate a checkout-local include root in the build tree, route build-time include paths through it, and retain the public executorch/... include namespace and installed layout.

Review this commit by starting with tools/cmake/Utils.cmake and the top-level CMakeLists.txt, then checking the standalone backend and example entrypoints, and finally test/test_worktree_build.sh.

Authored with assistance from Codex.

Fixes #6475

cc @digantdesai @freddan80 @per @zingo @oscarandersson8218 @mansnils @Sebastian-Larsson @robell

[pytorch-bot]

🔗 Helpful Links

🧪 See artifacts and rendered test results at hud.pytorch.org/pr/pytorch/executorch/22292

• 📄 Preview Python docs built from this PR

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❌ 1 New Failure, 2 Cancelled Jobs, 1 Unrelated Failure, 7 Unclassified Failures

As of commit 7a690f8 with merge base 80f7005 ():

NEW FAILURE - The following job has failed:

• pull / test-qnn-models-linux (dl3) / linux-job (gh)
  ##[error]fatal: unable to access 'https://github.com/NVIDIA/cutlass/': Error in the HTTP2 framing layer

UNCLASSIFIED FAILURES - DrCI could not classify the following jobs because the workflow did not run on the merge base. The failures may be pre-existing on trunk or introduced by this PR:

• Build macOS Wheels / pytorch/executorch / build-wheel-py3_10-cpu (gh) (this job did not run on the merge base, so DrCI cannot tell whether the failure is pre-existing)
• Build macOS Wheels / pytorch/executorch / upload / upload-wheel-py3_10-cpu (gh) (this job did not run on the merge base, so DrCI cannot tell whether the failure is pre-existing)
  Unable to download artifact(s): Artifact not found
• MLX / test-mlx / test-mlx (gh) (this job did not run on the merge base, so DrCI cannot tell whether the failure is pre-existing)
  AssertionError: Slot for getitem already set to Slot(id_type=<IdType.Tensor: 1>, id_space=<IdSpace.Output: 3>, idx=0), trying to set to Slot(id_type=<IdType.Tensor: 1>, id_space=<IdSpace.Input: 2>, idx=3)
• MLX / test-mlx-dflash / test-mlx-dflash (gh) (this job did not run on the merge base, so DrCI cannot tell whether the failure is pre-existing)
  AssertionError: Slot for getitem already set to Slot(id_type=<IdType.Tensor: 1>, id_space=<IdSpace.Output: 3>, idx=0), trying to set to Slot(id_type=<IdType.Tensor: 1>, id_space=<IdSpace.Input: 2>, idx=2)
• MLX / test-mlx-qwen35-moe / test-mlx-qwen35-moe (gh) (this job did not run on the merge base, so DrCI cannot tell whether the failure is pre-existing)
  AssertionError: Slot for getitem_8 already set to Slot(id_type=<IdType.Tensor: 1>, id_space=<IdSpace.Output: 3>, idx=2), trying to set to Slot(id_type=<IdType.Tensor: 1>, id_space=<IdSpace.Input: 2>, idx=4)
• MLX / test-mlx-stories110m / test-mlx-stories110m (gh) (this job did not run on the merge base, so DrCI cannot tell whether the failure is pre-existing)
  AssertionError: Slot for getitem already set to Slot(id_type=<IdType.Tensor: 1>, id_space=<IdSpace.Output: 3>, idx=0), trying to set to Slot(id_type=<IdType.Tensor: 1>, id_space=<IdSpace.Input: 2>, idx=2)
• trunk / test-llama-runner-mac (fp32, coreml) / macos-job (gh) (this job did not run on the merge base, so DrCI cannot tell whether the failure is pre-existing)
  AttributeError: 'BackendConfig' object has no attribute 'mps'

CANCELLED JOBS - The following jobs were cancelled. Please retry:

• pull / unittest / linux / linux-job (gh)
  ##[error]The operation was canceled.
• pull / unittest-editable / linux / linux-job (gh)
  ##[error]The operation was canceled.

FLAKY - The following job failed but was likely due to flakiness present on trunk:

• pull / test-qnn-testsuite-linux / test-backend-linux (qnn, models) / linux-job (gh) (matched linux rule in flaky-rules.json)
  The runner has received a shutdown signal. This can happen when the runner service is stopped, or a manually started runner is canceled.

This comment was automatically generated by Dr. CI and updates every 15 minutes.

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