changes to make it compatible with 64bit gcc

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@2790 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/CBackend/Writer.cpp

@@ -26,6 +26,7 @@
 using std::string;
 using std::map;
 using std::ostream;
+using std::cerr;
 
 static std::string getConstStrValue(const Constant* CPV);