ino64 status update and upgrade caution

[Ed Maste]

The ino64 project was committed to src last week[1][2] with
UPDATING notes added shortly thereafter [3][4][5].

As some people have been tripped up by the ino64 change I want to
emphasize again that the upgrade procedure described in UPDATING should
be followed exactly. The reboot after installing the new ino64 kernel,
and the addition of COMPAT_FREEBSD11 to custom kernel configurations,
are crucial steps.

Note that this upgrade is just the usual standard, documented procedure
and is required whenever new syscalls or other forwards-incompatible
changes are introduced. Prior to ino64 we have had a period without
any significant Application Binary Interface (ABI) or Kernel Binary
Interface (KBI) changes and it was possible to take shortcuts with the
upgrade procedure. The ino64 change is backwards-compatible but not
forwards-compatible and shortcuts must not be taken. (As a general
rule, it is safest to always use the full procedure unless you follow
the commit mailing list and are aware of which changes are not
foward-compatible.)

In addition, some users have created a libarchive.so.6 symlink to
libarchive.so.7, in an attempt to run older binaries on a fresh post-
ino64 install. Do not do this: libarchive.so.6 and libarchive.so.7
have an incompatible ABI and this will result in incorrect and
unpredictable behaviour.

The most recent -CURRENT package set was built prior to the ino64
commit, and thus will not work on a fresh ino64 install or snapshot
image. Until the next package set is available please build from ports,
or use Poudriere to build your own package set.

Most ports with a dependency on ino64 have now been patched. The
remaining ports which still need a change for ino64 are:

Port                        Responsible for # Skipped
--------------------------  ----------------------------
lang/gcc6-aux                 54
sysutils/py-psutil            13  (fix in review D10801)
devel/llvm38                   6
sysutils/py-psutil121          3
devel/radare2                  0
emulators/qemu-user-static     0
lang/ccl                       0
lang/dmd2                      0
lang/gcc5-aux                  0
lang/modula3                   0
lang/rust-nightly              0
lang/twelf                     0
lang/urweb                     0
net-mgmt/netdata               0

[1] https://svnweb.freebsd.org/changeset/base/318736
[2] https://svnweb.freebsd.org/changeset/base/318737
[3] https://svnweb.freebsd.org/changeset/base/318757
[4] https://svnweb.freebsd.org/changeset/base/318758
[5] https://svnweb.freebsd.org/changeset/base/318792