Copy stable/10@r272459 to releng/10.1 as part of
the 10.1-RELEASE process.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Reconnect a comment with its code.

Submitted by: bde

Bring poll.h up to conformance with POSIX.1-2001 by adding some
visibility conditionals, adding the nfds_t type, and changing the
poll() prototype a little. Update the manual to match.

Cleanup comments.

Remove all current poll(2) extensions except POLLINIGNEOF as they are now
unused.

Submitted by: bde

Remove __P

Fix select on fifos.

Backout revision 1.56 and 1.57 of fifo_vnops.c.

Introduce a new poll op "POLLINIGNEOF" that can be used to ignore
EOF on a fifo, POLLIN/POLLRDNORM is converted to POLLINIGNEOF within
the FIFO implementation to effect the correct behavior.

This should allow one to view a fifo pretty much as a data source
rather than worry about connections coming and going.

Reviewed by: bde

Fix typo: compatability -> compatibility.

Compatability is not an existing english word.

Synchronize the poll() prototype with the one provided in the
poll(2) manual page.

PR: 20677
Submitted by: "Ralf S. Engelschall" <rse@engelschall.com>

Change #ifdef KERNEL to #ifdef _KERNEL in the public headers. "KERNEL"
is an application space macro and the applications are supposed to be free
to use it as they please (but cannot). This is consistant with the other
BSD's who made this change quite some time ago. More commits to come.

$Id$ -> $FreeBSD$

Cleaned up some comments and ifdefs.

Add support for poll(2) on files. vop_nopoll() now returns POLLNVAL
if one of the new poll types is requested; hopefully this will not break
any existing code. (This is done so that programs have a dependable
way of determining whether a filesystem supports the extended poll types
or not.)

The new poll types added are:

POLLWRITE - file contents may have been modified
POLLNLINK - file was linked, unlinked, or renamed
POLLATTRIB - file's attributes may have been changed
POLLEXTEND - file was extended

Note that the internal operation of poll() means that it is impossible
for two processes to reliably poll for the same event (this could
be fixed but may not be worth it), so it is not possible to rewrite
`tail -f' to use poll at this time.

oops, I accidently committed a version without INFTIM at the last moment.
I'm not sure that this is the right place to put it, it is 'supposed' to
live in stropts.h.

Add sys/poll.h