undefined: wasmtime.Wat2Wasm on windows and macos (darwin)

When compiling with GOOS and GOARCH flags, compilation fails when GOOS is windows or darwin, but succeeds when it is linux.
I am running the `go build` command from linux (tried both fedora-41 locally and ubuntu-latest through build pipeline).

## Issue

Running:
`GOOS=windows GOARCH=amd64 go build -o test`
`GOOS=darwin GOARCH=amd64 go build -o test`

Produces:
`undefined: wasmtime.Wat2Wasm`

### Conditions

In the file it complains about, there is an import `"github.com/bytecodealliance/wasmtime-go/v29"` and a function call `wasmBytes, err := wasmtime.Wat2Wasm(wat)`.

## Not an issue

Running:
`GOOS=linux GOARCH=amd64 go build -o test`

Works fine without any compilation error.

---

Seems very strange to me that GOOS would affect something becoming undefined, so I'm suspecting something might be wrong? If there is an explanation for this or I am missing something, then perhaps it would be good to add that to the readme file. If I am the only one with this issue, do let me know.

### Workaround (In case someone else has this issue)

I managed to work around it by not cross-compiling and adding flag `CGO_ENABLED=1`. That made it work of macos.
For windows I also needed to download MinGW and set `CC=x86_64-w64-mingw32-gcc` and `CXX=x86_64-w64-mingw32-g++`

Leaving that here in case it helps anybody else.