Move some *at definitions to syscalls.list (bug 14138)

[Rich Felker]

On Mon, Sep 29, 2014 at 11:16:32PM +0000, Joseph S. Myers wrote:
> Continuing the move of syscall definitions to syscalls.list, where the
> removal of support for old kernel versions has made this possible,
> this patch moves definitions of various *at functions in
> sysdeps/unix/sysv/linux/.

I think this is premature. Some of these functions, especially
fchmodat, have serious bug reports open against them which cannot be
fixed if they're pure syscall wrappers. See:

https://sourceware.org/bugzilla/show_bug.cgi?id=14578

Rich