ref: d53908d15cd69c4a34def3865062f6746b9bb4a9
dir: /tests/cc/execute/0132-forward.c/
struct S *x; struct S { int i; struct S *next; }; int main(void) { struct S y, *p; unsigned n; y.i = 0; y.next = 0; x = &y; *x = y; for (n = 0, p = &y; p; ++n, p = p->next) ; return n; }