GeezerVison

mcpp-plugins 0.21.0. Tracks mcpp-community/mcpp#885 (design 2026-11-07, §4.3) and closes #887 on release.

Changes

• CMake cross contracts. A CMake cross build consumes the engine's compiler, flags, archiver and target contract when the action runs; a subproject installs a static library and an independent executable links it (tests/cmake-cross).
• Owned accelerator targets. Accelerator rules read complete, brace-aware requests and match exact implementation names. SYCL owns its code targets: sycl+{nvptx64-sm_89,nvptx64-sm_90} emits both NVIDIA images, sycl+{spir64,nvptx64-sm_89} emits SPIR-V beside NVIDIA; the CUDA toolkit is requested only for SYCL NVIDIA targets; the older target-inheritance spelling is accepted with a migration warning; unknown SYCL targets and unavailable AMD routes are refused. CUDA, HIP and Vulkan share the reader.
• Optional action progress. plugins-progress provides an atomic, rate-limited worker writer; CMake reports its configure and build-install stages and continues when the channel is absent or unwritable. The worker reads the channel through the UTF-8 environment API (Windows ACP 1252 verified).
• Incremental correctness. Object-surface assembly records payload content, so restat does not hide a changed payload behind an unchanged .incbin path.
• The system through modules. No unit includes a header or branches in the preprocessor (CI refuses both). A member asks a program for a fact through mcpp::plugins::tool::capture (its arguments as a vector, no shell); the CUDA rule opens the driver through mcpplibs::os::library; the test kit states each case's environment in its spawn options instead of writing its own; a platform difference of the building machine is if constexpr (mcpplibs::os::is_windows), so every host compiles every branch. mcpplibs.os (exactly 0.4.0, the release mcpp names) is a dependency of plugins-core and plugins-progress. docs/plugin-development.md §4 states the rule and the route for a C macro (mcpplibs.mwrap.libc).

Verification

• 50 plugin-logic cases; the CMake musl cross build and run; SYCL consumers in legacy, owned NVIDIA, multi-architecture and mixed forms, with the device images inspected; a dual-rule CUDA sm_90 + SYCL sm_89 consumer. GPU execution is not qualified (local driver: CUDA error 803).
• all-rules-compile, embed-consumer, embed-module-consumer, plugin-logic and island-interface build with the C-library change.

Release pins

• CI builds with the published mcpp 2026.11.7.1 on every lane; cross subprojects that link need it.
• Dependencies are exact releases named by identity (mcpplibs.os = "0.4.0").

SYCL libraries of several NVIDIA architectures

Each package's device link reads its own objects, so a library built for sycl+{nvptx64-sm_89,nvptx64-sm_90} links into a program with each image its own architecture's; tests/sycl-library-consumer builds it in CI and inspects the images. Not supported, and documented with the workaround: handing the SDK an archive of several NVIDIA architectures to device-link (a prebuilt SYCL .a, or a kernel calling another package's SYCL_EXTERNAL function) -- DPC++ 7.1.0's offload bundler matches its five-part bundle IDs to every NVPTX request (mcpp#899, an SDK defect).