Fix clang build issues.

llvm-svn: 169140
diff --git a/lldb/source/Symbol/ClangASTContext.cpp b/lldb/source/Symbol/ClangASTContext.cpp
index 99d96f7..3397b0e 100644
--- a/lldb/source/Symbol/ClangASTContext.cpp
+++ b/lldb/source/Symbol/ClangASTContext.cpp
@@ -34,6 +34,7 @@
 
 #include "clang/AST/ASTContext.h"
 #include "clang/AST/ASTImporter.h"
+#include "clang/AST/Attr.h"
 #include "clang/AST/CXXInheritance.h"
 #include "clang/AST/DeclObjC.h"
 #include "clang/AST/DeclTemplate.h"