func testReturnAfterGrow(t *testing.T) {
	// Use a new goroutine so that we get a small stack.
	c := make(chan int)
	go func() {
		c <- int(C.returnAfterGrow())
	}()
	if got, want := <-c, 123456; got != want {
		t.Errorf("got %d want %d", got, want)
	}
}

// Test that we can return a value from Go->C->Go if the Go code
// causes a stack copy.
func testReturnAfterGrowFromGo(t *testing.T) {