[CMAKE] removing ONEDPL_DEVICE_TYPE and ONEDPL_DEVICE_BACKEND

[danhoeflinger]

Removes ONEDPL_DEVICE_TYPE and ONEDPL_DEVICE_BACKEND settings from cmake, and triggers a fatal error if they are attempted to be used (suggesting instead the ONEAPI_DEVICE_SELECTOR environment variable equivalent to their proposed settings).

ONEDPL_DEVICE_TYPE and ONEDPL_DEVICE_BACKEND settings in CMake are confusing and may be misleading users about when they are and are not applied.

Before this PR, they would properly control the device filters when using ctest, but not when manually running the generated tests. It is not a compiler setting, but rather an environment variable for the runtime to adhere to. This also means if someone were to set their own ONEAPI_DEVICE_SELECTOR environment variable, it would be overridden by the ctest settings.

It is better for users to just directly use ONEAPI_DEVICE_SELECTOR.

I've made the decision also to only describe ONEAPI_DEVICE_SELECTOR and not SYCL_DEVICE_FILTER (which was used in the compiler pre 2023.1).

[Copilot]

Pull Request Overview

This PR removes the confusing CMake configuration options ONEDPL_DEVICE_TYPE and ONEDPL_DEVICE_BACKEND that only controlled device filtering for ctest but not manual test execution. The change encourages users to directly use the ONEAPI_DEVICE_SELECTOR environment variable for consistent device selection across all test execution methods.

• Removed CMake logic for ONEDPL_DEVICE_TYPE and ONEDPL_DEVICE_BACKEND configuration options
• Updated documentation to reference ONEAPI_DEVICE_SELECTOR instead of deprecated device type variables
• Modified CI workflows to use environment variable approach instead of CMake configuration

Reviewed Changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
test/CMakeLists.txt	Removed device selection logic that conditionally set environment variables for tests
documentation/library_guide/onedpl_gsg.rst	Updated device selection guidance to use ONEAPI_DEVICE_SELECTOR
documentation/library_guide/introduction/onedpl_gsg.rst	Updated device selection guidance to use ONEAPI_DEVICE_SELECTOR
cmake/README.md	Removed documentation for deprecated ONEDPL_DEVICE_TYPE and ONEDPL_DEVICE_BACKEND options
CONTRIBUTING.md	Updated build instructions to use environment variable approach
CMakeLists.txt	Replaced device type/backend logic with deprecation warnings
.github/workflows/ci-testing.yml	Updated CI to set ONEAPI_DEVICE_SELECTOR instead of using CMake options

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[dmitriy-sobolev]

LGTM