Silly followup question about interfacing with C, and bindgen:

I've got a library that 'really wants' to be built with GCC instead of LLVM - but ABI compatibility has been problematic

previously you all pointed out that gcc uses short enums -> that was indeed a problem and solvable via compiler flag

I recently stumbled across another thing: gcc seems to pack enums but LLVM does not

eg. 
```
typedef struct {
    uint8_t a;
    uint8_t b;
} Foo_t;

#[repr(C)] //doesn't work, needs #[repr(packed)]
struct Foo_t {
    a: u8,
    b: u8
}
```

This seems weird to me