[rand.dist.norm.f]

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@104035 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/chrono b/include/chrono
index 911a95e..1c79c68 100644
--- a/include/chrono
+++ b/include/chrono
@@ -264,7 +264,7 @@
 
 template <class _Rep, class _Period = ratio<1> > class duration;
 
-template <class T>
+template <class _Tp>
 struct __is_duration : false_type {};
 
 template <class _Rep, class _Period>