fix(build): construct SQLITE_TRANSIENT without tripping Zig 0.16 pointer-alignment check

[richardcase]

Problem

zig build fails on aarch64 (Apple Silicon) while compiling src/sqlite.zig:

error: pointer type '?*const fn (?*anyopaque) callconv(.c) void' requires aligned address
    SQLITE_TRANSIENT = __helpers.cast(sqlite3_destructor_type, -@as(c_int, 1));

Zig 0.16's translate-c expands the SQLITE_TRANSIENT macro ((void(*)(void*))-1) to @ptrFromInt(-1) for the destructor's function-pointer type. On aarch64 function pointers are >1-aligned, so the comptime alignment check rejects the unaligned -1. (On x86_64 the original compiled, which is why Phase 2 built on Linux.)

Fix

Construct the sentinel against an align(1) function-pointer type — which accepts any address — and bind through a matching extern declaration of sqlite3_bind_text:

const SqliteDestructor = ?*align(1) const fn (?*anyopaque) callconv(.c) void;
const SQLITE_TRANSIENT: SqliteDestructor = @ptrFromInt(@as(usize, @bitCast(@as(isize, -1))));
extern fn sqlite3_bind_text(stmt: ?*c.sqlite3_stmt, idx: c_int, text: [*c]const u8, n: c_int, destructor: SqliteDestructor) callconv(.c) c_int;

The destructor pointer is passed by value and never dereferenced, so this is ABI-safe and behaviorally identical to the C macro (SQLite receives the same (void*)-1 sentinel and copies the bound value). Single call site changed; works on both aarch64 and x86_64.

Verification (macOS / aarch64)

• zig build ✅ (previously failed — this is the fix)
• zig build test-c ✅ c_abi_test: PASS
• zig build test-unit ✅ (exit 0)

Known separate issue (not addressed here)

zig build test-poll still fails to compile on macOS — but for an unrelated, pre-existing reason: the mock-server in tests/core/poll_test.zig hardcodes Linux socket types (std.os.linux.SOL/SO, sockaddr). Phase 2 was developed and validated on Linux, where test-poll passes; the test harness was never made portable to macOS. That's a test-harness portability bug, distinct from this build break, and best fixed separately (and validated on both platforms).

🤖 Generated with Claude Code

https://claude.ai/code/session_012tRqDtnoLYPka4TGZ1BwYe