- Use if_get_counter() to fetch ifnet statistics.
- Report IFCOUNTER_OQDROPS to linprocfs. Wasn't there before.

Sponsored by:	Netflix
Sponsored by:	Nginx, Inc.
simple_httpd: cosmetic cleanups.

Many tab vs space cleanups.
Use setpgid() instead of setpgrp() which is more portable,

MFC after:	5 weeks
Enable ZFS debug flags to be modified via vfs.zfs.debug_flags.

This is primarily only of interest to ZFS developers, but it makes it
easier to get additional debugging.

Submitted by:	gibbs
MFC after:	1 month
Sponsored by:	Spectra Logic
MFSpectraBSD:	517074 on 2011/12/15 (by will), 662343 on 2013/03/20 (by gibbs)
lpr: replace setpgrp(2) with setpgid(2).

setpgid(2) is more portable than setpgrp(2).
The BSD variant of setpgrp is a wrapper for
setpgid(2) anyways.

MFC after:	5 weeks
unistd: move setpgrp(2) to the __BSD_VISIBLE section

Our setpgrp(2) differs from the specified by POSIX, which
only has one argument, and is only meant for compatibility
with BSD.

Reference:
http://pubs.opengroup.org/onlinepubs/009695399/functions/setpgrp.html

Pointed-out in:	openbsd-tech (2014-09-16)
MFC after:	6 weeks