implement EFBIG handling for heavily fragmented packets on the tx path.

ok claudio@
Remove "const" from the lsearch(3) manual's synopsis too.

Reminded by Rafael Neves
implement 'rootdev' parsing similar to what's already done in the kernel,
but this time for bootdev(). defaults to octcf0a if all else fails.
pass atomic_{cas,swap}_uint a volatile void * instead of a volatile
void **. the latter is really hard to cast for, and not what what
solaris does.

ok kettenis@
Cleanups:
- links are already ignored when creating the sums
- better CVSID match
Follow the recent addition of /usr/local/lib/pkgconfig and add
/usr/local/share/pkgconfig

ok sthen@
atomic_swap_ptr is special.

for jmatthew@
Fix privsep.c.  Call missing imsg_free() after imsg_get().  Also add
missing #include <net/if.h> to use IFNAMESIZ and replace some strncmp()
by startswith().
When the MAN_DIR/manpath.conf configuration file does not exist or is empty,
log the problem, hand the pg_error_internal() error page to the client,
and exit(3) in a controlled way instead of stumbling on and segfaulting
later.

Patch from Sebastien Marie <semarie-openbsd at latrappe dot fr>,
messages tweaked by me.
fix sorted output
missing newline
ugly ugly whitespace
As discussed with beck, tweak the wording for getentropy slightly so
that a certain kind of people don't go bonkers over "what is entropy".
it is what it is, input to PRNG's.
Since syslog messages are now sent via the sendsyslog(2) system call,
we no longer need the spread of dev/log AF_UNIX sockets all over the
various chroot spaces.
ok beck millert aja
Do not use the HTTP_HOST CGI variable,
just make the HTTP redirect Location: relative.
Less user input is good, it reduces the attack surface.
Besides, this removes one global variable and 4 lines of code.

Patch from Sebastien Marie <semarie-openbsd at latrappe dot fr>.
Document that getentropy() is async signal safe.

Pointed out by Jean-Philippe Ouellet
Oops, getentropy() is an "extension interface", not a "base interface"

Also, update the async signal safe list in signal(3) too (reminded by
deraadt)
sync
Cleanup portable arc4random fork detection code:

1. Use "len" parameter instead of sizeof(*rs).

2. Simplify the atfork handler to be strictly async signal safe by
simply writing to a global volatile sig_atomic_t object, and then
checking for this in _rs_forkdetect().  (Idea from discussions with
Szabolcs Nagy and Rich Felker.)

3. Use memset(rs, 0, sizeof(*rs)) to match OpenBSD's MAP_INHERIT_ZERO
fork semantics to avoid any skew in behavior across platforms.

ok deraadt
The pf forward tests were running rdr-to and nat-to simultaneously
only.  Change address layout and add individual tests for each
feature rdr-to and nat-to and rdr-to together with nat-to.