Code style: Replace tab with space.
diff --git a/include/ndn-cpp/encoding/oid.hpp b/include/ndn-cpp/encoding/oid.hpp
index bcbcfe9..bc0dd25 100644
--- a/include/ndn-cpp/encoding/oid.hpp
+++ b/include/ndn-cpp/encoding/oid.hpp
@@ -7,7 +7,7 @@
  */
 
 #ifndef NDN_OID_HPP
-#define	NDN_OID_HPP
+#define NDN_OID_HPP
 
 #include <vector>
 #include <string>