[libc++] Avoid deprecation warning in the implementation of __has_rebind

Author: ldionne

libcxx/include/memory

@@ -847,7 +847,9 @@ struct __has_rebind
 private:
     struct __two {char __lx; char __lxx;};
     template <class _Xp> static __two __test(...);
+    _LIBCPP_SUPPRESS_DEPRECATED_PUSH
     template <class _Xp> static char __test(typename _Xp::template rebind<_Up>* = 0);
+    _LIBCPP_SUPPRESS_DEPRECATED_POP
 public:
     static const bool value = sizeof(__test<_Tp>(0)) == 1;
 };