Add #includes that were pruned from already #included files

llvm-svn: 2173
diff --git a/llvm/lib/Analysis/Writer.cpp b/llvm/lib/Analysis/Writer.cpp
index 1e873bf..b4d5375 100644
--- a/llvm/lib/Analysis/Writer.cpp
+++ b/llvm/lib/Analysis/Writer.cpp
@@ -10,8 +10,10 @@
 #include "llvm/Analysis/Dominators.h"
 #include "llvm/Analysis/LoopInfo.h"
 #include "llvm/Analysis/InductionVariable.h"
+#include "llvm/Assembly/Writer.h"
 #include <iterator>
 #include <algorithm>
+#include <string>
 using std::ostream;
 using std::set;
 using std::vector;