[klibc] Support for pselect, ppoll, sync_file_range, splice, tee

New system call bonanza.  Defined splice() and tee() in <sys/splice.h>;
sync_file_range() in <unistd.h>, pselect() in <sys/select.h> (per POSIX)
and ppoll in <sys/poll.h>.  Make <poll.h> -> <sys/poll.h>.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
9 files changed