Update Clang for 3.5 rebase (r209713).

Change-Id: I8c9133b0f8f776dc915f270b60f94962e771bc83
diff --git a/lib/Frontend/DependencyGraph.cpp b/lib/Frontend/DependencyGraph.cpp
index 4bff3db..051b7f9 100644
--- a/lib/Frontend/DependencyGraph.cpp
+++ b/lib/Frontend/DependencyGraph.cpp
@@ -79,7 +79,7 @@
   SourceManager &SM = PP->getSourceManager();
   const FileEntry *FromFile
     = SM.getFileEntryForID(SM.getFileID(SM.getExpansionLoc(HashLoc)));
-  if (FromFile == 0) 
+  if (!FromFile)
     return;
 
   Dependencies[FromFile].push_back(File);