Hopefully fix windows build due to non-standard pair implementation.

llvm-svn: 174169
diff --git a/clang/lib/Format/Format.cpp b/clang/lib/Format/Format.cpp
index 0326499..d638221 100644
--- a/clang/lib/Format/Format.cpp
+++ b/clang/lib/Format/Format.cpp
@@ -595,7 +595,7 @@
     // Insert start element into queue.
     std::multimap<unsigned, QueueItem> Queue;
     Queue.insert(std::pair<unsigned, QueueItem>(
-        0, QueueItem(InitialState, Edge(false, NULL))));
+        0, QueueItem(InitialState, Edge(false, (const LineState *) 0))));
     std::map<LineState, Edge> Seen;
 
     // While not empty, take first element and follow edges.