new syscall stub support for ia64 libc

[David Mosberger]

>>>>> On Fri, 31 Oct 2003 08:01:14 +0100, Jakub Jelinek <jakub@redhat.com> said:

  Jakub> Cannot tcbhead_t's private field be reused for the sysinfo pointer
  Jakub> actually on IA-64?

As long as we can make it appear at offsets -8, that would be OK.

  Jakub> That way 32 bytes wouldn't have to be wasted at end of struct
  Jakub> pthread, it would be at the same location in linuxthreads as
  Jakub> well as NPTL build

That's not sufficient.  The offset must be the same across _all_ libcs,
so that non-libc code can use the new syscall stubs as well.

	--david