ARM long branch stub: thumb

[Paul Brook]

> > Waitaminute. This code is completely bogus.
>
> Indeed!
> Actually, I merely tried to adapt the existing "Thumb->(non-interworking
> aware) ARM" glue. If you look at the comments just above
> arm_allocate_glue_section_space(), you'll see that the existing glue
> creates a frame... oops.

The "non-interworking aware" veneers are something completely different, and 
documented to not work in many cases.

Paul