90/90 regression tests pass (+ffi-03-large-struct).
vendors/ffi_large_struct/{.h,.c} defines:
Big24 — 24 B, three s64 (byval params + sret return)
Big48 — 48 B, six s64 (same path, larger)
`make / rotate-or-reverse / sum` helpers per shape. The sx-side
example imports via `#source` only and declares matching structs +
hand-written #foreign decls.
Snapshot pins today's >16-byte aggregate ABI now that the
emit_llvm.zig sret-return transform is in place (previous commit).
That gives us a regression net for all four C-ABI aggregate slots
in one place:
≤8 B int — i64 coercion (ffi-01 vec-likes)
9..16 B int — [2 x i64] coercion (ffi-02 Pair64/Quad32, 101)
16 B HFA — struct, no coercion (ffi-02 Vec2/Vec4f)
>16 B — byval params + sret (this commit)
2463eea1d4