ref: 5cee3c5e3fdc511a468879104c08a1aa0e8c2b0f dir: /tests/cc/execute/0155-struct-compl.c/
extern struct X x; int foo(); int main() { extern struct X x; return &x != 0; } struct X {int v;}; int foo() { x.v = 0; return x.v; }