For compatibility with old C compilers, don't use const in C code.
diff --git a/ndn-cpp/encoding/BinaryXMLDecoder.c b/ndn-cpp/encoding/BinaryXMLDecoder.c
index 5798364..f68e9b9 100644
--- a/ndn-cpp/encoding/BinaryXMLDecoder.c
+++ b/ndn-cpp/encoding/BinaryXMLDecoder.c
@@ -7,7 +7,7 @@
 #include "BinaryXML.h"
 #include "BinaryXMLDecoder.h"
 
-const char *ndn_BinaryXMLDecoder_decodeTypeAndValue(struct ndn_BinaryXMLDecoder *self, unsigned int *type, unsigned int *valueOut) 
+char *ndn_BinaryXMLDecoder_decodeTypeAndValue(struct ndn_BinaryXMLDecoder *self, unsigned int *type, unsigned int *valueOut) 
 {
   unsigned int value = 0;
   
@@ -28,5 +28,5 @@
 	}
 
 	*valueOut = value;
-  return (const char *)0;
+  return (char *)0;
 }