field; unrepresentable fields are replaced with opaque byte arrays.  A
C union translates into a struct containing the first union member and
perhaps additional padding.  C arrays become Go arrays.  C pointers
become Go pointers.  C function pointers become Go's uintptr.
C void pointers become Go's unsafe.Pointer.

For example, mpz_t is defined in <gmp.h> as:

	typedef unsigned long int mp_limb_t;

	typedef struct
	{
		int _mp_alloc;