Hi Maintainers,

This patch adds pointer mangling support for Aarch64.
Regressed by cross testing glibc tests on V8 Foundation model running
a linaro open embedded image.

Ok for trunk? Please provide your feedback.

ChangeLog.aarch64:
-----------------------------
2013-12-26  Venkataramanan Kumar  <venkataramanan.kumar@linaro.org>

* sysdeps/aarch64/__longjmp.S (__longjmp): Demangle sp
        and lr when restoring register values.
* sysdeps/aarch64/setjmp.S (__sigsetjmp): Mangle sp and lr
before storing register values.
* sysdeps/arm/jmpbuf-unwind.h (_jmpbuf_sp): Remove.
* sysdeps/aarch64/jmpbuf-offsets.h (_jmpbuf_sp): Add.
(JB_FRAME_ADDRESS): call  _jmpbuf_sp.
* sysdeps/aarch64/sysdep.h (LDST_PCREL) : New macros.
(LDST_GLOBAL): Likewise.
* sysdeps/unix/sysv/linux/aarch64/sysdep.h (PTR_MANGLE): New macro.
(PTR_DEMANGLE): Likewise.
(PTR_MANGLE2): Likewise.
(PTR_DEMANGLE2): Likewise.

regards
Venkat.