Fix build on Ubuntu 10.04.

llvm-svn: 109208
diff --git a/clang/lib/Frontend/ASTUnit.cpp b/clang/lib/Frontend/ASTUnit.cpp
index 5b2af15..41627a5 100644
--- a/clang/lib/Frontend/ASTUnit.cpp
+++ b/clang/lib/Frontend/ASTUnit.cpp
@@ -34,6 +34,7 @@
 #include "llvm/System/Host.h"
 #include "llvm/System/Path.h"
 #include <cstdlib>
+#include <cstdio>
 using namespace clang;
 
 PrecompiledPreamble::~PrecompiledPreamble() {