debug flags and g_type_init()

[Owen Taylor <otaylor redhat com>]

Currently:

 - g_type_init() can be called multiple times
 - debug flags not set the first time will be silently ignored.

So, in the rare case that someone wants to set the debug
flags, they have to do:

 g_type_init (my_debug_flags);

 gtk_init (&argc, &argv);

Why not remove the debug flags argument to g_type_init()
and have a separate g_type_set_debug_flags()? This has
the advantages:

 - We omit the mysterious 0 from g_type_init(0)
 - We can put out a meaningful error if someone tries to 
   set the debug flags after GType is initialized.

Regards,
                                        Owen