# `ci/winstub/` — empty Windows import-lib stub

`libsynchronization.a` here is an **empty `ar` archive** (8 bytes: `!<arch>\n`),
referenced by `.cargo/config.toml` via `-L native=ci/winstub` for the Windows
release targets.

## Why

The D1 release matrix cross-compiles Windows binaries from Linux with
`cargo zigbuild` (see `docs/ci/adr/`). Rust's `std` links `-lsynchronization`
for its `WaitOnAddress`-based thread parking. That import library is normally
provided by Rust's `rust-mingw` "self-contained" component — which `rust-overlay`
does not ship — and Zig's bundled mingw doesn't carry it either, so the link
fails with:

```
error: unable to find dynamic system library 'synchronization'
```

The functions it would import (`WaitOnAddress`, `WakeByAddressSingle`,
`WakeByAddressAll`) are **forwarded by `kernel32.dll`**, which is already linked,
so they resolve at link and run time without a real `synchronization` import
library. An **empty** stub is therefore sufficient: it satisfies the `-l`
lookup and contributes no symbols.

## Regenerating

```
zig ar rcs ci/winstub/libsynchronization.a
```