[PATCH] Support -pie for aarch64*-elf targets.

[Nick Clifton]

Hi Roland,

> Other aarch64-* targets and other *-elf targets support -pie,
> so this looks like it was just a simple oversight.
> 
> OK for trunk and 2.27 branch?

OK for trunk.

Not sure about the branch - Tristan will have to decide.  But it 
is awfully close to release time.

Cheers
  Nick