On other archs we'll not define it so that open_tmpfile() falls back to
unguessable name + unlink.
#ifndef TMP_MAX
# define TMP_MAX 238328
#endif
+
+#if defined(__i386__) || defined(__x86_64__)
+
+/* The precise definition of __O_TMPFILE is arch specific, so let's
+ * just define this on x86 where we know the value. */
+
+#ifndef __O_TMPFILE
+#define __O_TMPFILE 020000000
+#endif
+
+/* a horrid kludge trying to make sure that this will fail on old kernels */
+#ifndef O_TMPFILE
+#define O_TMPFILE (__O_TMPFILE | O_DIRECTORY)
+#endif
+
+#endif