For compatibility with old C compilers, don't use const in C code.
diff --git a/ndn-cpp/encoding/BinaryXMLStructureDecoder.h b/ndn-cpp/encoding/BinaryXMLStructureDecoder.h
index 58a595f..504a1bd 100644
--- a/ndn-cpp/encoding/BinaryXMLStructureDecoder.h
+++ b/ndn-cpp/encoding/BinaryXMLStructureDecoder.h
@@ -40,8 +40,8 @@
  * @param inputLength the number of bytes in input.
  * @return 0 for success, else an error string
  */
-const char *ndn_BinaryXMLStructureDecoder_findElementEnd
-  (struct ndn_BinaryXMLStructureDecoder *self, const unsigned char *input, unsigned int inputLength);
+char *ndn_BinaryXMLStructureDecoder_findElementEnd
+  (struct ndn_BinaryXMLStructureDecoder *self, unsigned char *input, unsigned int inputLength);
 
 #ifdef	__cplusplus
 }