Add support for g_auto[s]list(Type)

This lets you do g_autoptr style cleanup of GList that does deep freeing.

https://bugzilla.gnome.org/show_bug.cgi?id=791342

glib/docs.c

@@ -2607,6 +2607,62 @@
  * Since: 2.44
  */
 
+/**
+ * g_autolist:
+ * @TypeName: a supported variable type
+ *
+ * Helper to declare a list variable with automatic deep cleanup.
+ *
+ * The list is deeply freed, in a way appropriate to the specified type, when the
+ * variable goes out of scope.  The type must support this.
+ *
+ * This feature is only supported on GCC and clang.  This macro is not
+ * defined on other compilers and should not be used in programs that
+ * are intended to be portable to those compilers.
+ *
+ * This is meant to be used to declare lists of a type with a cleanup
+ * function.  The type of the variable is a GList *.  You
+ * must not add your own '*'.
+ *
+ * This macro can be used to avoid having to do explicit cleanups of
+ * local variables when exiting functions.  It often vastly simplifies
+ * handling of error conditions, removing the need for various tricks
+ * such as 'goto out' or repeating of cleanup code.  It is also helpful
+ * for non-error cases.
+ *
+ * See also g_autoslist(), g_autoptr() and g_steal_pointer().
+ *
+ * Since: 2.56
+ */
+
+/**
+ * g_autoslist:
+ * @TypeName: a supported variable type
+ *
+ * Helper to declare a singly linked list variable with automatic deep cleanup.
+ *
+ * The list is deeply freed, in a way appropriate to the specified type, when the
+ * variable goes out of scope.  The type must support this.
+ *
+ * This feature is only supported on GCC and clang.  This macro is not
+ * defined on other compilers and should not be used in programs that
+ * are intended to be portable to those compilers.
+ *
+ * This is meant to be used to declare lists of a type with a cleanup
+ * function.  The type of the variable is a GSList *.  You
+ * must not add your own '*'.
+ *
+ * This macro can be used to avoid having to do explicit cleanups of
+ * local variables when exiting functions.  It often vastly simplifies
+ * handling of error conditions, removing the need for various tricks
+ * such as 'goto out' or repeating of cleanup code.  It is also helpful
+ * for non-error cases.
+ *
+ * See also g_autolist(), g_autoptr() and g_steal_pointer().
+ *
+ * Since: 2.56
+ */
+
 /**
  * G_DEFINE_AUTOPTR_CLEANUP_FUNC:
  * @TypeName: a type name to define a g_autoptr() cleanup function for