Bulk build test by naddy.

and valloc() are not in the current version, while posix_memalign() mkstemp(),
and mkdtemp() are, and setstate()'s argument has lost a bogus 'const'.
ok millert@ jmc@ espie@ kettenis@; ports build testing by naddy@

from sys/unistd.h to unistd.h.
From Brad; ok millert and me

as NULL has. This will (hopefully) simplify ports where the user
passes the device string.

ok guenther, millert (and me); bulk build test by naddy

Okay otto@

* strptime(3) was introduced in XPG 4.0
* clock_gettime(3) and friends were introduced in 1003.1b-1993
* asctime_r(3) and friends were introduced in 1003.1c-1995
and conditionally provide prototypes and associated types accordingly.
This makes our <time.h> standards compliant except for some functions that are
still missing.
ok guenther@

friends in <time.h>.  The kernel needs access to the associated #defines, but
can't get them from <time.h>, so introduce a new header <sys/_time.h> and
include that from <time.h> for userland and <sys/time.h> for the kernel.
ok matthew@, guenther@, millert@

suggested by deraadt@

of POSIX-2001, without the XSI qualifier.  Adjust conditionals to match.
ok millert@

requests the pre-standardized version
requested by millert@

typedef regardless of __BSD_VISIBLE, and eliminate the dirfd() macro.
ok guenther@

use "const struct dirent **" instead of "const void *".  Also, add
__restrict to readdir_r().
ok matthew@

to be pruned later when DIR is made an opaque type.
ok guenther@; prodding by brad@ for VLC and other ports

Prompted in a mail to tech@ by Jan Klemkow (j-dot-klemkow-at-wemelug-dot-de)
but this is based on NetBSD's implementation instead with some tweaks by me.
Further improvements would happen in tree.
ok millert@; discussed with many others
ports cleanup by naddy@, sthen@. Antti Harri, Gonzalo L. R. and myself.

FreeBSD's implementation via Frank Denis, with various cleanups and
tweaks by me.
ok deraadt@, guenther@; discussions and tweaks from many others
jmc@ promises to help me further with the man pages in tree

Includes friendly linker warning to wake up those dumb enough to use it.
Committing for kettenis@, who ran away to the hills after writing it

ok guenther

Ok sthen@, millert@, dcoppa@

and add an 'rtableid' keyword to ps.
Add rtable id, thread id, and socket splice info to struct kinfo_file2
and make fstat display socket splice information.
Remove old KVM_PROC2 and kinfo_proc2 interfaces; bump libkvm major
Socket splice info and corrections from bluhm@  "Lovely" deraadt@

ok beck@, guenther@, millert@, miod@

instead of <pthread.h>.
ok guenther@, millert@

Correct the namespace protections for sigreturn(), sigwait(), and psignal()
ok millert@

fail with errno set to ERANGE if not enough room is provided. Similar for
getlogin_r() so remove minbytes enforcement attribute.
ok kettenis@ guenther@ deraadt@ on getcwd, deraadt@ on getlogin_r.

character support changes based on code from FreeBSD.
ok espie guenther; man page help from schwarze

fchmodat(2), fstatat(2), mkdirat(2), mkfifoat(2), mknodat(2),
faccessat(2), fchownat(2), linkat(2), readlinkat(2), renameat(2),
symlinkat(2), unlinkat(2), utimensat(2), futimens(2), and
fdopendir(3).
"Minor" libc bump.
Tested in a bulk build by naddy@
Much help from guenther@, thib@, tedu@, oga@, and others.
ok deraadt@, naddy@

dd_flags is renamed to the placeholder position dd_unused so that
we can spot "broken software" which assumes we have Jan Simon Pendry's
union mounts (we don't have them, and won't have them ever again).
__opendir2 question spotted by matthew
verified to not break ports by sthen

and complex math routines are complete.  OK kettenis@.

extended-precision support.  Mostly from Cephes.

changes to libevent and zlib headers sent to the upstream maintainers.
ok jmc@ (for typos), millert@

of a 1 when creating signal masks.
ok millert@

commit, and deal with problems (if any) in tree.
Note that this adds the following functions.  Ports with hacks might
need adjustments.
nexttoward(3), fma(3), nexttowardf(3), fmaf(3), acoshl(3), asinhl(3),
atanhl(3), coshl(3), sinhl(3), tanhl(3), expl(3), expm1l(3), logl(3),
log10l(3), log1pl(3), log2l(3), modfl(3), cbrtl(3), hypotl(3),
powl(3), erfl(3), erfcl(3), lgammal(3), tgammal(3), ceill(3),
floorl(3), lrintl(3), llrintl(3), roundl(3), lroundl(3), llroundl(3),
truncl(3), fmodl(3), remainderl(3), remquol(3), nextafterl(3),
nexttowardl(3), fmal(3).
With this commit, our library implements all functionality required
by C99.  Documentation bits will follow.

ok deraadt matthew

of NULL was incorrect for c++ compilers that aren't
gcc (or pretend to be gcc like clang).
ok miod@

precludes -Wredundant-declarations with multiple includes.
okay millert@

of wcscasecmp() and wcsncasecmp().  Noticed by naddy@ OK espie@

Doesn't matter much since C++ ABI used by GCC doesn't mangle variable
names;  however technically is required by Section 7.5 of the C++ spec.
Discussed with/OK guenther@, matthew@.

- add nearbyint, nearbyintf and nearbyintl implemented using fenv

"Yes, go ahead then" deraadt

reentrant getgrent functions (getgrgid_r, getgrnam_r).
seems reasonable to millert@, ok deraadt@

Based on our vfprintf etc. implementations. Wide character parts based on
NetBSD but with lots of macros expanded. Minor bump for libc.
ok kettenis espie

feedback & ok guenther@, matthew@

Kernel and bootblocks still use the old 0L value until all the NULL abuses
in the code are fixed.