Extract runtime compatibility fixes from PR 41

docs/reviews/pr41-adaptation.md

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+# PR #41 compatibility adaptation
+
+[Original PR](https://github.com/lucannez64/darling-lol/pull/41)
+
+This adaptation keeps the compatibility corrections that can be implemented and
+checked independently of a fabricated machine or security identity. It starts
+from main after PRs #43 and #42. It does not claim to resolve account bans.
+
+## Included
+
+- Foundation returns the installed system's full version/build description,
+  falling back to ProductVersion and then Unknown. Numeric version comparisons
+  read ProductVersion directly, independently of the localized or overridden
+  description. No macOS version or build number is invented.
+- physicalMemory queries 64-bit hw.memsize, then retries hw.physmem with its
+  correct 32-bit buffer width. The existing failure fallback is preserved.
+- Unknown ptrace requests return EINVAL instead of an uninitialized value.
+  Existing handled requests retain their behavior.
+- Unsupported page-accounting and task-policy requests return
+  KERN_NOT_SUPPORTED, initializing output counts where appropriate. Unsupported
+  VM-region and thread-info flavors return KERN_INVALID_ARGUMENT. These calls
+  no longer terminate darlingserver through unsafe stubs.
+- The kernel-debugger capability query returns false and initializes its output.
+- The 32-bit debug-state conversion passes the converted structure instead of
+  the address of its input pointer. Hardware debug-state support remains
+  unsupported.
+
+## Work left outside this adaptation
+
+The original PR's rendered source changes were inspected against its merge base,
+so patch regeneration noise was excluded from this review.
+
+- Its darling.patch deletes the existing vDSP arith.c and fft.c implementations.
+  Those working routines must be preserved.
+- GPU reporting is already implemented using actual Vulkan device properties.
+  A fixed Radeon Pro name and 4 GB budget would replace that behavior.
+- The per-host platform ID fix is already merged. A separate configurable
+  identity feature would need an explicit schema, stable defaults, import
+  validation, and migration tests before replacing it. Automatic Apple serial,
+  NVRAM, OS-version, and model fabrication is excluded.
+- CPUID trapping changes the SIGSEGV path and advertises a specific Intel CPU
+  on every host. It needs a separate design around actual host capabilities,
+  instruction safety, signal chaining, and performance; it is not necessary
+  for the compatibility corrections above.
+- csops, AMFI, SIP, and debugger APIs must reflect implemented checks and state.
+  Fixed signing identities, fabricated trust-cache membership, and successful
+  setters that do not apply their settings cannot serve as those implementations.
+- IOKit registry lookup/property routines should be extracted with bounds,
+  lifetime, traversal, and serialization tests, independent of synthetic NVRAM.
+- Launcher environment and descriptor changes need a defined ownership boundary.
+  Blanket removal of driver variables or closing descriptors 3 through 256 can
+  remove intentional configuration and live descriptors. Keep #42's path setup.
+- Log verbosity, descriptor leaks in shellspawn, CPU-frequency units, and other
+  independent correctness fixes can be separate changes with focused checks.
+
+## Validation
+
+The patch-level C regression tests compile the actual patched function bodies
+with inert RPC substitutes and exercise error returns, output initialization,
+null output pointers, unknown ptrace requests, and existing ptrace branches:
+
+```sh
+python3 -m unittest discover -s tests
+python3 scripts/prepare.py --check-only
+python3 scripts/validate.py
+python3 tools/riot-launcher-offline-check.py
+python3 tools/riot-input-offline-check.py
+python3 tools/riot-runtime-cleanup-offline-check.py
+```
+
+With the adapted patches prepared and Foundation rebuilt, the guest probe checks
+full version/build reporting, numeric version independence from an overridden
+description, and physicalMemory against 64-bit hw.memsize:
+
+```sh
+python3 build/runtime/tools/build-riot-process-info-check.py
+darling shell /Volumes/SystemRoot/ABSOLUTE_PROJECT_PATH/build/riot-process-info-check
+```
+
+The probe must load the rebuilt Foundation using the configured runtime or an
+isolated DYLD_FRAMEWORK_PATH. The adaptation was checked with an isolated
+Foundation build; the installed runtime and running server were not replaced.