Merge from stable/11 bspatch, portsnap, and libarchive fixes:

=== bspatch ===

MFS r306213: bspatch Capsicumization, sanity checks, and other improvements

r304691: bspatch: apply style(9)

Make style changes (and trivial refactoring of open calls) now in order
to reduce noise in diffs for future capsicum changes.

r304807 (allanjude): Capsicumize bspatch

Move all of the fopen() and open() calls to the top of main()

Restrict each FD to least privilege (read/seek only, write only, etc)

cap_enter(), and make all except the output FD read/seek only.

r304821: bspatch: remove output file in the case of error

r305486: bspatch: add sanity checks on sizes to avoid integer overflow

Note that this introduces an explicit 2GB limit, but this was already
implicit in variable and function argument types.

This is based on the "non-cryptanalytic attacks against freebsd
update components" anonymous gist. Further refinement is planned.

r305737: bspatch: remove superfluous newlines from errx strings

r305822: bspatch: use #define for header size instead of magic number

r306026: bspatch: Remove backwards-compatibility sys/capability.h support

bspatch previously included sys/capability.h or sys/capsicum.h based
on __FreeBSD_version, as FreeBSD is the upstream for bsdiff and we may
see this file incorporated into other third-party software.

The Capsicum header is now installed as sys/capsicum.h in stable/10 and
FreeBSD 10.3, so we can just use sys/capsicum.h and simplify the logic.

With this change, bspatch is identical between head, stable/11 and releng/11.0.

=== portsnap ===

MFS r305648 (delphij): MFC r305469:

Ensure that we always open only files that is named by explicitly
using shell redirections instead of having gzip(1) to decide what
file to open.

Issue reported in the "non-cryptanalytic attacks against freebsd
update components" anonymous gist.

=== libarchive ===

MFS r305754 (mm): MFC r305422:

Sync libarchive with vendor

Vendor issues fixed:
PR #777: Multiple bugfixes for setup_acls()

This includes a bugfix for a bug that caused ACLs not to be read properly
for files and directories inside subdirectories and as a result not being
stored or being incorrectly stored in tar archives.

MFS r306321 (mm): MFC r305819:

Sync libarchive with vendor including important security fixes.

Issues fixed (FreeBSD):
PR #778: ACL error handling
Issue #745: Symlink check prefix optimization is too aggressive
Issue #746: Hard links with data can evade sandboxing restrictions

This update fixes the vulnerability #3 and vulnerability #4 as reported in
"non-cryptanalytic attacks against FreeBSD update components".
https://gist.github.com/anonymous/e48209b03f1dd9625a992717e7b89c4f

Fix for vulnerability #2 has already been merged.

Approved by: re (gjb), so (glebius)

Copy stable/11@r303970 to releng/11.0 as part of the 11.0-RELEASE
cycle.

Prune svn:mergeinfo from the new branch, and rename it to RC1.

Update __FreeBSD_version.

Use the quarterly branch for the default FreeBSD.conf pkg(8) repo and
the dvd1.iso packages population.

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

Fix bspatch heap overflow vulnerability.

Obtained from: Chromium
Reported by: Lu Tung-Pin
Security: FreeBSD-SA-16:25.bspatch
Approved by: re (so@ blanket)

Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

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

Cleanup unnecessary semicolons from utilities we all love.

Check for (old|new)size + 1 overflows off_t.

PR: 204230
MFC after: 1 week

Use meaningful errno for ssize_t overflow in read().
Catch size_t overflow in malloc().

PR: 204230
MFC after: 1 week

Add META_MODE support.

Off by default, build behaves normally.
WITH_META_MODE we get auto objdir creation, the ability to
start build from anywhere in the tree.

Still need to add real targets under targets/ to build packages.

Differential Revision: D2796
Reviewed by: brooks imp

Convert to usr.bin/ to LIBADD
Reduce overlinking

use .Mt to mark up email addresses consistently (part3)

PR: 191174
Submitted by: Franco Fichtner <franco at lastsummer.de>

Make usage printing more consistent with other tools.

- Introduce a separate usage() function.
- Don't use argv[0]. Directly name the application, as we do elsewhere.
- Don't prepend the application name.
- Don't print two newlines.

Remove trailing whitespace per mdoc lint warning

Disussed with: gavin
No objection from: doc
Approved by: joel
MFC after: 3 days

Silence bogus warning when compiling with gcc46:
error: 'pos' may be used uninitialized in this function

Reviewed by: cperciva
Approved by: dim
MFC after: 3 days

mdoc: move CAVEATS, BUGS and SECURITY CONSIDERATIONS sections to the
bottom of the manpages and order them consistently.

GNU groff doesn't care about the ordering, and doesn't even mention
CAVEATS and SECURITY CONSIDERATIONS as common sections and where to put
them.

Found by: mdocml lint run
Reviewed by: ru

Build usr.bin/ with WARNS=6 by default.

Also add some missing $FreeBSD$ to keep svn happy.

Add notes pointing out that bsdiff does not store file hashes and
bspatch thus does not verify file hashes, and that consequently it
is recommended that users store hashes separately and verify files
before and after running bspatch.

Requested by: BugMagnet
MFC after: 1 week

Portability fix for non-POSIX operating systems: Open files in binary mode.

PR: bin/106358
Submitted by: techtonik at php dot net

Fix up markup.

Include ../Makefile.inc, since without it programs get installed in the
wrong place.

Pointy hat to: cperciva

Add bsdiff and bspatch to the base system. These are tools for
constructing and applying binary patches; in particular, they perform
well (in the sense of constructing small patches) for executable code.
Both portsnap (coming to the base system Real Soon Now) and FreeBSD
Update (coming to the base system a bit later) use bspatch.

This is the same code as the bsdiff-4.2 which has been in the ports
tree (misc/bsdiff) for the past year, with the following exceptions:
1. The license is now the traditional 2-clause BSD;
2. Instead of forking and execing bzip2, the code now uses libbz2; and
3. Some minor changes have been made to fit this code into the base
system (adding $FreeBSD$ tags, putting bsdiff and bspatch into separate
directories, etc.)

This code is rather ugly and has lots of style bugs (mostly because I
wrote it before I had ever heard of style(9)). Some day I'll come
back and clean it up.

Discussed on: freebsd-arch
MFC before: 5.5-RELEASE
Tested by: Several million users (earlier version).