Update LLVM for 3.5 rebase (r209712).

Change-Id: I149556c940fb7dc92d075273c87ff584f400941f
diff --git a/lib/ExecutionEngine/MCJIT/SectionMemoryManager.cpp b/lib/ExecutionEngine/MCJIT/SectionMemoryManager.cpp
index f1dd5a6..9ceaa90 100644
--- a/lib/ExecutionEngine/MCJIT/SectionMemoryManager.cpp
+++ b/lib/ExecutionEngine/MCJIT/SectionMemoryManager.cpp
@@ -79,7 +79,7 @@
                                                           ec);
   if (ec) {
     // FIXME: Add error propagation to the interface.
-    return NULL;
+    return nullptr;
   }
 
   // Save this address as the basis for our next request