new syscall stub support for ia64 libc

[David Mosberger <davidm at napali dot hpl dot hp dot com>]

Now that NPTL etc. have settled, I'd like to renew the effort in
getting the new system call stubs supported on ia64.  As you may
recall, the new syscall stubs are designed to support light-weight
system calls (by taking advantage of the EPC instruction).  The
light-weight syscalls can yield huge performance improvements.  For
example, gettimeofday() and sigprocmask() run about 3 times faster as
lightweight syscalls.

What I'd like to see is something that makes it possible for
non-threaded and NPTL apps to take advantage of the new syscall stubs.
If LinuxThreads apps don't get the benefit, that's OK, I suppose.

Does this sound reasonable?  If so, how should I go about this?
Should I re-send the (forward-ported) version of the original patch
that I did so you can see what's involved?  Any other suggestions?

Thanks,

	--david