Add a for_each_string_list_item macro

This is more lightweight than a call to for_each_string_list function with
callback function and a cookie argument.

Signed-off-by: Alex Riesen <raa.lkml@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

string-list.h

@@ -20,10 +20,12 @@ void string_list_clear(struct string_list *list, int free_util);
 typedef void (*string_list_clear_func_t)(void *p, const char *str);
 void string_list_clear_func(struct string_list *list, string_list_clear_func_t clearfunc);
 
-/* Use this function to iterate over each item */
+/* Use this function or the macro below to iterate over each item */
 typedef int (*string_list_each_func_t)(struct string_list_item *, void *);
 int for_each_string_list(struct string_list *list,
 			 string_list_each_func_t, void *cb_data);
+#define for_each_string_list_item(item,list) \
+	for (item = (list)->items; item < (list)->items + (list)->nr; ++item)
 
 /* Use these functions only on sorted lists: */
 int string_list_has_string(const struct string_list *list, const char *string);