Add const correctness to public interfaces

Gerard Krol, g dot c dot krol at student dot tudelft dot nl

Update version number to 0.9



git-svn-id: http://svn.metaparadigm.com/svn/json-c/trunk@27 327403b1-1117-474d-bef2-5cb71233fd97

json_util.c

@@ -85,7 +85,7 @@ struct json_object* json_object_from_file(char *filename)
 
 int json_object_to_file(char *filename, struct json_object *obj)
 {
-  char *json_str;
+  const char *json_str;
   int fd, ret;
   unsigned int wpos, wsize;