- clang++ -std=c++11 -xc++ -c test.c
- clang -std=c11 -c test.c
- g++ -std=c++11 -xc++ -c test.c
- gcc -std=c11 -c test.c
test.c:
```
#ifdef __cplusplus
#include <cstddef>
#else
#include <stddef.h>
#endif
struct foo {
_Alignas(_Alignof(max_align_t)) unsigned char ivars[32];
};
```