Mark LWG#2260 as complete. We already did the right thing, so I just added tests to ensure that we continue to DTRT.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@338936 91177308-0d34-0410-b5e6-96231b3b80d8

test/std/utilities/memory/pointer.traits/pointer.traits.functions/pointer_to.pass.cpp

@@ -39,6 +39,7 @@ int main()
 {
     {
         int i = 0;
+        static_assert((std::is_same<A<int>, decltype(std::pointer_traits<A<int> >::pointer_to(i))>::value), "");
         A<int> a = std::pointer_traits<A<int> >::pointer_to(i);
         assert(a.t_ == &i);
     }

test/std/utilities/memory/pointer.traits/pointer_to.pass.cpp

@@ -23,6 +23,7 @@ int main()
 {
     {
         int i = 0;
+        static_assert((std::is_same<int *, decltype(std::pointer_traits<int*>::pointer_to(i))>::value), "");
         int* a = std::pointer_traits<int*>::pointer_to(i);
         assert(a == &i);
     }

www/cxx1z_status.html

@@ -442,7 +442,7 @@
 	<tr><td><a href="https://wg21.link/LWG2777">2777</a></td><td>basic_string_view::copy should use char_traits::copy</td><td>Issaquah</td><td>Complete</td></tr>
 	<tr><td><a href="https://wg21.link/LWG2778">2778</a></td><td>basic_string_view is missing constexpr</td><td>Issaquah</td><td>Complete</td></tr>
  	<tr><td></td><td></td><td></td><td></td></tr>
-	<tr><td><a href="https://wg21.link/LWG2260">2260</a></td><td>Missing requirement for Allocator::pointer</td><td>Kona</td><td></td></tr>
+	<tr><td><a href="https://wg21.link/LWG2260">2260</a></td><td>Missing requirement for Allocator::pointer</td><td>Kona</td><td>Complete</td></tr>
 	<tr><td><a href="https://wg21.link/LWG2676">2676</a></td><td>Provide filesystem::path overloads for File-based streams</td><td>Kona</td><td>Complete</td></tr>
 	<tr><td><a href="https://wg21.link/LWG2768">2768</a></td><td>any_cast and move semantics</td><td>Kona</td><td>Complete</td></tr>
 	<tr><td><a href="https://wg21.link/LWG2769">2769</a></td><td>Redundant const in the return type of any_cast(const any&amp;)</td><td>Kona</td><td>Complete</td></tr>
@@ -504,7 +504,7 @@
 <!-- 	<tr><td></td><td></td><td></td><td></td></tr> -->
   </table>
 
-  <p>Last Updated: 22-May-2018</p>
+  <p>Last Updated: 3-Aug-2018</p>
 </div>
 </body>
 </html>