Fix <rdar://problem/10226704>

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@141054 91177308-0d34-0410-b5e6-96231b3b80d8

include/tuple

@@ -639,11 +639,6 @@ tie(_Tp&... __t)
 template <class _Up>
 struct __ignore_t
 {
-    _LIBCPP_INLINE_VISIBILITY
-    __ignore_t() {}
-    template <class _Tp>
-        _LIBCPP_INLINE_VISIBILITY
-        __ignore_t(_Tp&&) {}
     template <class _Tp>
         _LIBCPP_INLINE_VISIBILITY
         const __ignore_t& operator=(_Tp&&) const {return *this;}