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;
		int _mp_size;

	for i := 0; i < 10000; i++ {
		testCFNumberRef()
		testCFDateRef()
		testCFBooleanRef()
		// Allocate some memory, so eventually the write barrier is enabled
		// and it will see writes of bad pointers in the test* functions below.
		byteSliceSink = make([]byte, 1024)
	}
}

var byteSliceSink []byte

func testCFNumberRef() {
	var v int64 = 0