Merge branch 'ab/free-and-null'

A common pattern to free a piece of memory and assign NULL to the
pointer that used to point at it has been replaced with a new
FREE_AND_NULL() macro.

* ab/free-and-null:
  *.[ch] refactoring: make use of the FREE_AND_NULL() macro
  coccinelle: make use of the "expression" FREE_AND_NULL() rule
  coccinelle: add a rule to make "expression" code use FREE_AND_NULL()
  coccinelle: make use of the "type" FREE_AND_NULL() rule
  coccinelle: add a rule to make "type" code use FREE_AND_NULL()
  git-compat-util: add a FREE_AND_NULL() wrapper around free(ptr); ptr = NULL

sequencer.c

@@ -1212,8 +1212,7 @@ struct todo_list {
 static void todo_list_release(struct todo_list *todo_list)
 {
 	strbuf_release(&todo_list->buf);
-	free(todo_list->items);
-	todo_list->items = NULL;
+	FREE_AND_NULL(todo_list->items);
 	todo_list->nr = todo_list->alloc = 0;
 }