Add missing include.

llvm-svn: 206110
diff --git a/dragonegg/src/Aliasing.cpp b/dragonegg/src/Aliasing.cpp
index 12650c5..3c82b2b 100644
--- a/dragonegg/src/Aliasing.cpp
+++ b/dragonegg/src/Aliasing.cpp
@@ -29,6 +29,7 @@
 #include "llvm/ADT/Twine.h"
 #include "llvm/IR/LLVMContext.h"
 #include "llvm/IR/MDBuilder.h"
+#include "llvm/IR/Metadata.h"
 
 // System headers
 #include <gmp.h>