tst-clone3: Use __NR_futex_time64 if we don't have __NR_futex

We can't include sysdep.h in the test case (it introduces lots of
strange failures) so __NR_futex isn't redifined to __NR_futex_time64 by
64-bit time_t 32-bit archs (y2038 safe).

To allow the test to pass let's just do the __NR_futex_time64 syscall if
we don't have __NR_futex defined.

Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>

sysdeps/unix/sysv/linux/tst-clone3.c

@@ -56,7 +56,11 @@ f (void *a)
 static inline int
 futex_wait (int *futexp, int val)
 {
+#ifdef __NR_futex
   return syscall (__NR_futex, futexp, FUTEX_WAIT, val);
+#else
+  return syscall (__NR_futex_time64, futexp, FUTEX_WAIT, val);
+#endif
 }
 
 static int