Enable sibcalls on hppa-unknown-linux-gnu

[John David Anglin]

> Note that when the incoming argument pointer is a call-clobbered hard
> register (like %r29 for PA64) generic parts of the compiler will arrange
> for %r29 to be copied into a pseudo and that pseudo should be used for
> incoming argument pointer references within the function.

Ah, I was wrong.  It's the copy that prevents sibcalls.

Dave
-- 
J. David Anglin                                  dave.anglin@nrc.ca
National Research Council of Canada              (613) 990-0752 (FAX: 952-6605)