Patch to avoid history duplicates applied

[Pavel Roskin]

Hello!

>          * utilunix.c (destroy_groups): Use g_tree_foreach() instead of
>          obsolete g_tree_traverse().
>
> glib-1.2 has no g_tree_foreach() function, so some more checks are needed.

Reverted.  Thank you!

It looks like we need a configure option to select glib version.  It
existed at some point before 4.6.0, but I removed it to avoid confusing
users.  Now I see that I was wrong.  Such option is needed for testing,
and the code can easily break without testing.

--with-glib12 will be restored, and the gmodule patch will be applied,
hopefully this weekend.

-- 
Regards,
Pavel Roskin