- Unused variable warning (when building in release mode):
```bash
wasm-micro-runtime/samples/wasi-threads/wasm-apps/no_pthread.c:44:9:
warning: variable 'thread_id' set but not used [-Wunused-but-set-variable]
int thread_id;
```
- When using the multi-module example and changing the files in `wasm-apps`,
they don't get recompiled when the sample is rebuilt. Adding `BUILD_ALWAYS`
as it's done in other samples.
This syscall doesn't need allocating stack or TLS and it's expected from the application
to do that instead. E.g. WASI-libc already does this for `pthread_create`.
Also fix some of the examples to allocate memory for stack and not use stack before
the stack pointer is set to a correct value.
