add back a #include needed on some builders.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@172938 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Serialization/ASTReader.cpp b/lib/Serialization/ASTReader.cpp
index 660e661..676bd9d 100644
--- a/lib/Serialization/ASTReader.cpp
+++ b/lib/Serialization/ASTReader.cpp
@@ -51,6 +51,7 @@
 #include "llvm/Support/SaveAndRestore.h"
 #include "llvm/Support/system_error.h"
 #include <algorithm>
+#include <cstdio>
 #include <iterator>
 
 using namespace clang;