Merged revisions 201261 via svnmerge from

https://origsvn.digium.com/svn/asterisk/branches/1.4

........
  r201261 | kpfleming | 2009-06-17 07:03:25 -0500 (Wed, 17 Jun 2009) | 9 lines
  
  Correct AST_LIST_APPEND_LIST behavior when list to be appended is empty.
  
  When the list to be appended is empty, and the list to be appended to is *not*,
  AST_LIST_APPEND_LIST would actually cause the target list to become broken,
  and no longer have a pointer to its last entry. This patch fixes the problem.
  
  (reported by Stanislaw Pitucha on the asterisk-dev mailing list)
........


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@201262 65c4cc65-6c06-0410-ace0-fbb531ad65f3

include/asterisk/linkedlists.h

@@ -765,15 +765,18 @@ struct {								\
  * calling this macro (the list entries are \b moved to the target list).
  */
 #define AST_LIST_APPEND_LIST(head, list, field) do {			\
-      if (!(head)->first) {						\
+	if (!(list)->first) {						\
+		break;							\
+	}								\
+	if (!(head)->first) {						\
 		(head)->first = (list)->first;				\
 		(head)->last = (list)->last;				\
-      } else {								\
+	} else {							\
 		(head)->last->field.next = (list)->first;		\
 		(head)->last = (list)->last;				\
-      }									\
-      (list)->first = NULL;						\
-      (list)->last = NULL;						\
+	}								\
+	(list)->first = NULL;						\
+	(list)->last = NULL;						\
 } while (0)
 
 #define AST_RWLIST_APPEND_LIST AST_LIST_APPEND_LIST