Remove the THIS_FUNCTION_IS_DEPRECATED define, we stopped using it long ago.

json_object.h

@@ -17,16 +17,6 @@
 #ifndef _json_object_h_
 #define _json_object_h_
 
-#ifdef __GNUC__
-#define THIS_FUNCTION_IS_DEPRECATED(func) func __attribute__((deprecated))
-#elif defined(_MSC_VER)
-#define THIS_FUNCTION_IS_DEPRECATED(func) __declspec(deprecated) func
-#elif defined(__clang__)
-#define THIS_FUNCTION_IS_DEPRECATED(func) func __deprecated
-#else
-#define THIS_FUNCTION_IS_DEPRECATED(func) func
-#endif
-
 #ifdef __GNUC__
 #define JSON_C_CONST_FUNCTION(func) func __attribute__((const))
 #else