Fix four clang 22 regen regressions (size_t constant macros, __unaligned leak, namespace remap, NativeTypeName namespace)

[tannergooding]

Regenerating terrafx.interop.windows against ClangSharp v22.1.8 (clang 22.1.8) surfaced four issues, all rooted in clang 22's changed type representation (it folds qualifiers into a type's spelling, desugars fewer sugar types on its own, and drops the enclosing namespace from an in-scope reference). Each fix is a focused commit with a golden-file regression test.

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Bug 1 -- size_t constant-expression macros emit an uncompilable ref readonly getter (blocking)

An unsigned/size_t-typed constant expression macro (e.g. ARRAYSIZE(x) - 1, sizeof(...)) took the experimental ref readonly path and emitted a property body that was just the folded expression -- no return, no ; -- so it failed with CS1002 (and leaked the internal __size_t type name). This was the dominant break in the regen (~152 CS1002 across 26 files). Root cause: clang 22 hands back a sugar type IsType<T> no longer recognized, so the macro fell off the constant path. Desugar the unrecognized sugar as a fallback so these import as plain constants again, matching v21.

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Bug 2 -- __unaligned + elaborated struct specifier leaks into C# (blocking)

clang 22 folds local qualifiers into a tag type's spelling and no longer emits an ElaboratedType, so a UNALIGNED FAR pointer typedef leaked __unaligned struct tagFoo* -- not valid C#. Resolve the tag name through its decl so the qualifier keywords drop and the elaborated struct specifier resolves to the record type.

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Bug 3 -- namespace-qualified (dotted) remap keys stopped applying at use-sites

A --remap keyed by a namespace-qualified name (e.g. Gdiplus.PointF=@GpPointF) applied to the type declaration but not to references, silently renaming Gp* back to the unprefixed names the Gp prefix existed to avoid. Same root cause as Bug 2 -- the reference was matched by printed string rather than by decl. Resolving through the decl makes the remap apply consistently at declaration and use-site.

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Symptom C -- NativeTypeName loses the C++ namespace

clang 22 omits the enclosing namespace from a reference spelled while that namespace is in scope (a using namespace or a reference from within the namespace), where-as older releases always spelled it, so Gdiplus::Status degraded to Status (~1332 lines in the regen, and it interacts with the Bug 3 remap). Rebuild the dropped Namespace:: prefix from the referenced decl for typedef, record (including by-pointer), and enum references. The prepend is a no-op when there's no namespace ancestor, the printed name already carries the scope, or the decl is anonymous, so no existing (C-only self-host) baselines change.

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Each fix adds a golden-file regression test (SizeTMacroBinding, UnalignedTypeBinding, NamespaceRemap, NamespaceNativeTypeName). Full generator suite: 4116 passed / 0 failed, 0 warnings.

Note

This description was drafted by Copilot.