some cleanup; tested by sthen@ on a ports build

relevant. from Mark Karpilovskij.
ok millert

cleanups.  From Jan Kokemueller.  OK deraadt@

(w/ _dlctl reference) into static executables.  It's all Mark's code so
put his preferred copyright on it.
ok kettenis@

to control which symbols are exported from the shared library.
ok guenther@, deraadt@, jca@

pledge for a new execve image immediately upon start.  Also introduces
"error" which makes violations return -1 ENOSYS instead of killing the
program ("error" may not be handed to a setuid/setgid program, which
may be missing/ignoring syscall return values and would continue with
inconsistant state)
Discussion with many
florian has used this to improve the strictness of a daemon

_libc___cxa_thread_atexit_impl reference on gcc architectures that breaks
the build.

interface is also made available as __cxa_thread_atexit_impl to satisfy the
needs of GNU libstdc++.
ok guenther@, millert@

PF ruleset. This is not a complete block on _pbuild being able to communicate
(e.g. non-TCP/UDP protocols don't have a PCB with userid, so PF can't restrict
in those cases) but avoids some cases, and in particular makes it more obvious
when a port does things like download extra distfiles or dependencies
as part of the build process. Slight tweak from a diff by espie@.

to builtins like mem{set,cpy,move} and __stack_smash_handler.  So, when
building with clang, instead mark those as protected visibility to get rid
of the PLT relocations.  We can't take the address of them then, but that's
ok: it's a build-time error not a run-time error.
ok kettenis@

discussed at length with benno, beck, deraadt, and florian

now misalign things.
ok guenther@

__cxa_thread_atexit() implementation.
ok guenther@

with "warning: " since 2003, so the messages themselves need not
contain the prefix anymore.
From Scott Cheloha
ok jca, deraadt

"nice" deraadt@
OK benno

OK benno, sthen

/dev/arandom any longer.  ok deraadt@

currently serves no purpose.
ok rpe, agreement from deraadt and halex

etc) from underlying switch interface instead of handling this on its
own.
Diff from carlos cardenas, Thanks!
ok reyk@

OK tb@

prodded by Raf Czlonka
OK tb@

one location under /usr/share/relink.
Be more specific in src/etc/rc reorder_libs() what filesystems
need r/w remount and ensure that their mount state is restored.
Idea and positive feedback from deraadt@
OK aja@ tb@

While it is not clear (to me) why that ports ends up with corrupted
shared libs, reverting those changes fixes the issue and should allow us
to close p2k17 more smoothly.
Discussed with a bunch, ok ajacoutot@ guenther@

ttyB* minor numbers change; be sure to rerun MAKEDEV if you do not
upgrade with bsd.rd
Adapted from NetBSD by miod@

From Raf Czlonka.
ok halex

on the stack instead of mallocing the list and move the APIs from libpthread
to libc so that they can be used inside libc.
Note: the standard was explicitly written to permit/support this
"macro with unmatched brace" style and it's what basically everyone
else already does.  We xor the info with random cookies with a
random magic to detect/trip-up overwrites.
Major bump to both libc and libpthread due to the API move.
ok mpi@

sysctl_conf() spawns a subshell.  This prevents that the new process
limits affect the daemons started during boot.
OK rpe@ halex@

but not all.  From Peter J. Philipp.

which results in an internal double free when internal functions are not
in use.
ok otto@

For the moment it only includes <sys/exec_elf.h> but the goal is to
stop pulling it directly and also replace <elf_abi.h> at least for
base applications.
ok deraadt@, jasper@, naddy@

Create only /dev/urandom as device.
Create /dev/random and /dev/arandom as symlinks.
Drop /dev/srandom, which has been unused for a long time.
/dev/arandom will go away at a later point.
Discussed with guenther@, ok deraadt@

implementation is now spread between libc and librthread.  No changes
to the content
ok mpi@

Move tmpdir for reordering library from /tmp to /usr/lib.
This allows to have /tmp mounted noexec.
prompted by reports on misc@
OK deraadt@ tj@ tb@

OK deraadt@ jca@ jmc@

OK deraadt@

combine the two find(1) invocations into one.
From Klemens Nanni; ok tb@

fixes parsing of the example configuration
OK benno@