Fix stupid but harmless type-o.  Fixes http://llvm.org/bugs/show_bug.cgi?id=15657.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@178691 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/thread b/include/thread
index 8d3aab2..f41ea29 100644
--- a/include/thread
+++ b/include/thread
@@ -328,7 +328,7 @@
 template <class _Fp, class ..._Args, size_t ..._Indices>
 inline _LIBCPP_INLINE_VISIBILITY
 void
-__threaad_execute(tuple<_Fp, _Args...>& __t, __tuple_indices<_Indices...>)
+__thread_execute(tuple<_Fp, _Args...>& __t, __tuple_indices<_Indices...>)
 {
     __invoke(_VSTD::move(_VSTD::get<0>(__t)), _VSTD::move(_VSTD::get<_Indices>(__t))...);
 }
@@ -340,7 +340,7 @@
     __thread_local_data().reset(new __thread_struct);
     std::unique_ptr<_Fp> __p(static_cast<_Fp*>(__vp));
     typedef typename __make_tuple_indices<tuple_size<_Fp>::value, 1>::type _Index;
-    __threaad_execute(*__p, _Index());
+    __thread_execute(*__p, _Index());
     return nullptr;
 }