GladeBaseEditor->build_child() use correct type for paramenters
Fixes bug 704600 "Cannot add items to menu hierarchy - assertion `GLADE_IS_WIDGET_ADAPTOR (adaptor)' failed"

  GladeWidget * (*build_child)      (GladeBaseEditor *, GladeWidget *, GType);

glin-genmarshal does not have a specific type for GType thus back in the day UINT was used instead.
But this is not correct in systems where GType is bigger than UINT