Fix error messages

Error messages did not reflect actual function names.

json_object.c

@@ -945,14 +945,15 @@ int json_c_set_serialization_double_format(const char *double_format, int global
 		}
 		tls_serialization_float_format = double_format ? strdup(double_format) : NULL;
 #else
-		_json_c_set_last_err("json_c_set_option: not compiled with __thread support\n");
+		_json_c_set_last_err("json_c_set_set_serialization_double_format: not compiled "
+		                     "with __thread support\n");
 		return -1;
 #endif
 	}
 	else
 	{
-		_json_c_set_last_err("json_c_set_option: invalid global_or_thread value: %d\n",
-		                     global_or_thread);
+		_json_c_set_last_err("json_c_set_serialization_double_format: invalid "
+		                     "global_or_thread value: %d\n", global_or_thread);
 		return -1;
 	}
 	return 0;

json_util.c

@@ -91,7 +91,7 @@ struct json_object *json_object_from_fd_ex(int fd, int in_depth)
 
 	if (!(pb = printbuf_new()))
 	{
-		_json_c_set_last_err("json_object_from_file: printbuf_new failed\n");
+		_json_c_set_last_err("json_object_from_fd_ex: printbuf_new failed\n");
 		return NULL;
 	}
 
@@ -101,7 +101,7 @@ struct json_object *json_object_from_fd_ex(int fd, int in_depth)
 	if (!tok)
 	{
 		_json_c_set_last_err(
-		    "json_object_from_fd: unable to allocate json_tokener(depth=%d): %s\n", depth,
+		    "json_object_from_fd_ex: unable to allocate json_tokener(depth=%d): %s\n", depth,
 		    strerror(errno));
 		printbuf_free(pb);
 		return NULL;
@@ -113,7 +113,7 @@ struct json_object *json_object_from_fd_ex(int fd, int in_depth)
 	}
 	if (ret < 0)
 	{
-		_json_c_set_last_err("json_object_from_fd: error reading fd %d: %s\n", fd,
+		_json_c_set_last_err("json_object_from_fd_ex: error reading fd %d: %s\n", fd,
 		                     strerror(errno));
 		json_tokener_free(tok);
 		printbuf_free(pb);
@@ -137,8 +137,8 @@ struct json_object *json_object_from_file(const char *filename)
 
 	if ((fd = open(filename, O_RDONLY)) < 0)
 	{
-		_json_c_set_last_err("json_object_from_file: error opening file %s: %s\n", filename,
-		                     strerror(errno));
+		_json_c_set_last_err("json_object_from_file: error opening file %s: %s\n",
+		                     filename, strerror(errno));
 		return NULL;
 	}
 	obj = json_object_from_fd(fd);
@@ -155,14 +155,14 @@ int json_object_to_file_ext(const char *filename, struct json_object *obj, int f
 
 	if (!obj)
 	{
-		_json_c_set_last_err("json_object_to_file: object is null\n");
+		_json_c_set_last_err("json_object_to_file_ext: object is null\n");
 		return -1;
 	}
 
 	if ((fd = open(filename, O_WRONLY | O_TRUNC | O_CREAT, 0644)) < 0)
 	{
-		_json_c_set_last_err("json_object_to_file: error opening file %s: %s\n", filename,
-		                     strerror(errno));
+		_json_c_set_last_err("json_object_to_file_ext: error opening file %s: %s\n",
+		                     filename, strerror(errno));
 		return -1;
 	}
 	ret = _json_object_to_fd(fd, obj, flags, filename);
@@ -202,7 +202,7 @@ static int _json_object_to_fd(int fd, struct json_object *obj, int flags, const
 	{
 		if ((ret = write(fd, json_str + wpos, wsize - wpos)) < 0)
 		{
-			_json_c_set_last_err("json_object_to_file: error writing file %s: %s\n",
+			_json_c_set_last_err("json_object_to_fd: error writing file %s: %s\n",
 			                     filename, strerror(errno));
 			return -1;
 		}