static init c struct with array filed

[test via Digitalmars-d-learn]

```c
struct Test {
    int32_t a;
}
struct Test2 {
    int32_t a;
    Test arr[];
}
```
I need static const init Test2, then pass it to c library 
late(third library, can not change the type def).


I am not sure how to do it in D.