diff --git a/lib/Frontend/DocumentXML.cpp b/lib/Frontend/DocumentXML.cpp
index 9ed10c8..2f7e995 100644
--- a/lib/Frontend/DocumentXML.cpp
+++ b/lib/Frontend/DocumentXML.cpp
@@ -17,6 +17,7 @@
 #include "clang/AST/ASTContext.h"
 #include "clang/Basic/SourceManager.h"
 #include "llvm/ADT/StringExtras.h"
+#include "llvm/Config/config.h"
 #include <cstdio>
 
 namespace clang {