new syscall stub support for ia64 libc

[David Mosberger]

>>>>> On Mon, 8 Dec 2003 20:09:58 +0100, Jakub Jelinek <jakub@redhat.com> said:

  Jakub> It will not.  The thing is that MD_FALLBACK_FRAME_STATE_FOR
  Jakub> special handles the signal trampoline only if it is between:

  Jakub> #define IA64_GATE_AREA_START 0xa000000000000100LL
  Jakub> #define IA64_GATE_AREA_END   0xa000000000020000LL

Ah, I didn't realize it was testing for such a narrow range.
Switching the read-only and execute-only pages should be OK.  At least
I can't think of anything that would depend on the order of those two
pages.

	--david