[ARM] global Thumb to ARM branches broken

[Christophe LYON]

> The reason for having this logic in the assembler is for the case where
> you have function calls / branches to transform from one state to the
> other and push the rest out to the linker to handle by veneering. For
> arch versions that didn't have the equivalent {x} variant we would want
> to push out the relocations.

I don't understand why your patch to md_pcrel_from_section does not 
involve S_IS_EXTERNAL, while your patch to md_apply_fix does. Could you 
explain it to me?

>> Finally, I am not sure about the new behaviour of
>> arm_force_relocation(): it now returns 1 in several new occurrences, but
>> the corresponding relocations do not appear in the object file (see
>> blx-local test)
>
> I'll have to take another look at this and get back to you.
>
Actually, it seems that I misunderstood the purpose of 
arm_force_relocation. It just triggers a flag for gas internal use, 
which is set appropriately in md_apply_fix.

Christophe.