Emit fake constructor

[AZHenley]

Currently, member initializations are being emitted which is not valid C.

struct foobar {
    bool hungry = false;
    int number = 3;
};
...
struct foobar * myobj = malloc(sizeof(struct foobar));

Should be:

struct foobar {
    bool hungry;
    int number;
};
void _foobar(struct foobar* self) {
    hungry = false;
    number = 3;
}
...
struct foobar * myobj = malloc(sizeof(struct foobar));
_foobar(myobj);