Add note that some of these links are dead for now.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@179950 91177308-0d34-0410-b5e6-96231b3b80d8

www/cxx_status.html

@@ -405,6 +405,9 @@ provisionally named C++1y.  The following table describes which C++1y features
 have been implemented in Clang and in which Clang version they became
 available.</p>
 
+<p>Note: many of the links to papers here will not work until the
+ISO/IEC JTC1/SC22/WG21 post-Bristol mailing ships.</p>
+
 <table width="689" border="1" cellspacing="0">
  <tr>
     <th>Language Feature</th>