Casting to gpointer from gulong generates the following warning with
64bit Windows target MinGW:
gstplaybin2.c: In function 'pad_added_cb':
gstplaybin2.c:3476:7: error: cast to pointer from integer of different size [-Werror=int-to-pointer-cast]
(gpointer) group_id_probe_handler);
^
cc1: all warnings being treated as errors
We should cast to guintptr from gulong before we cast to gpointer.
https://bugzilla.gnome.org/show_bug.cgi?id=754755
ab64b00b48