yet more C++ standards-compliance stuff.

llvm-svn: 25028
diff --git a/llvm/lib/Target/CBackend/Writer.cpp b/llvm/lib/Target/CBackend/Writer.cpp
index ce7f4c8..dd45582 100644
--- a/llvm/lib/Target/CBackend/Writer.cpp
+++ b/llvm/lib/Target/CBackend/Writer.cpp
@@ -39,6 +39,7 @@
 #include "llvm/Config/config.h"
 #include <algorithm>
 #include <iostream>
+#include <ios>
 #include <sstream>
 using namespace llvm;