Address darwin compile issue introduced in r15013, due to _IOC_NONE

git-svn-id: svn://svn.valgrind.org/valgrind/trunk@15028 a5019735-40e9-0310-863c-91ae7b9d1cf9
diff --git a/none/tests/ioctl_moans.c b/none/tests/ioctl_moans.c
index 65fbc02..ed05e7b 100644
--- a/none/tests/ioctl_moans.c
+++ b/none/tests/ioctl_moans.c
@@ -8,7 +8,11 @@
    The choice of values here needs to match the logic in
    ML_(PRE_unknown_ioctl) and take into account that _IOC_NONE
    is not == 0 everywhere. */
+# if !defined(VGO_darwin)
 #define IOCTL_REQUEST_BASE (0x12345670 | _IOC(_IOC_NONE,0,0,0))
+# else
+#define IOCTL_REQUEST_BASE  0x12345670
+# endif
 
 int main(int argc, const char *argv[])
 {