04: glib: g_list_free_1 should return ->next

[Guido Draheim <guidod-2003- gmx de>]

The glib2 function g_list_free_1 is currently defined as
void     g_list_free_1         (GList            *list);

This is not the best option, the function is actually
called in many places to free the head of a glist. In
about *all* places that includes an iteration on to the
->next list item.

Currently, all these places make up their own tmp variable
to store the ->next pointer for the iteration, ie. they
do something like
   GList* tmp = list->next;
   g_list_free_1 (list);
   list = tmp;

All these code points may be collapsed if the g_list_free_1
function would be redeclared to return the ->next pointer
all by itself, with the code parts becoming simply:
   list = g_list_free_1 (list);

Looking at the implementation of g_list_free_1, a developer
can easily see that the ->next value is accessed anyway, so
it would not be problematic to load the ->next value into
the return-register.

GList*     g_list_free_1         (GList            *list);

In effect, the glib code would be smaller, faster, more
readable, and consequently maintainable. Old code may
still ignore the return value, so that a change has only
minimal effect on existing code.

-- cheers, guido                     counter.li.org #81555