This testcase needs IOCTL_REQUEST_BASE to be set to some bogus
value with the platform dependent "no direction" flag set.
That flag wasn't being set for Darwin and so the testcase was
failing.
#define IOCTL_REQUEST_BASE (0x12345670 | _IOC(_IOC_NONE,0,0,0))
# elif defined(VGO_freebsd)
#define IOCTL_REQUEST_BASE (0x12345670 | _IO(0,0))
+# elif defined(VGO_darwin)
+#define IOCTL_REQUEST_BASE (0x12345670 | _IOC(IOC_VOID,0,0,0))
# else
#define IOCTL_REQUEST_BASE 0x12345670
# endif