struct declaration (silly question)

Hello Guys,
Silly question - what is the most elegant way of compiling a code similar
to this one?

<code>
typedef struct a {
  b_t *b;
} a_t;

typedef struct b {
  a_t *a;
} b_t;

int main(void) {

  return 0;
}
</code>

my solution is to simply change type "b_t" to "void" but I'm not sure
if that's the best way of dealing with this issue.

Thanks,

-- 
Marcin Kasprzak