Updates to the list of CPUs supported by the amd64 platform

MFC after:	3 days
Skip :sethostname_basic because it messes up the test host's hostname

Convert code from #if defined(__FreeBSD__) to #ifdef __FreeBSD__
Port t_kevent to FreeBSD

Submitted by: pho
Port t_mincore to FreeBSD

Mark :mincore_resid as atf_tc_expect_fail on FreeBSD because of new bug
discovered in running the tests (it succeeded from earlier on in the year to
September/October on FreeBSD, at least)

Submitted by: pho
Port h_atexit to FreeBSD

__cxa_atexit varies between FreeBSD and NetBSD, and thus we must use pointers
instead of static fields in the BSS. More extensive discussion is included in
the source code

In collaboration with: kib
Submitted by: pho
Expect :snprintf_posarg_error to blow up with a SIGSEGV on !NetBSD OSes
Disable testcases 12 and 15-22 on FreeBSD

Submitted by: pho
Add new atf_tc_expect_fail to fflush_err; this is a new (within the past couple months) bug
Skip :fopen_regular on !NetBSD because it's a NetBSD specific test

Submitted by: pho
Expect :sscanf_whitespace to fail on !NetBSD OSes

Submitted by: pho
Port h_hash and t_sha2 to FreeBSD

t_sha2 contains dirty copy-paste hacks that need to be fixed with the openssh
OpenBSD compat layer

Submitted by: pho
Fix up module unload for syscall_module_handler consumers.

After r273707 it was registering syscalls as static.

This fixes hwpmc module unload.

Reported by: markj
add an rc.d script to automatically grow the specified FS...  It has
been tested on both MBR and GPT...  It won't be enabled until you add
growfs_enable="YES" and will only run on first boot..
filedesc: lock filedesc lock in fdcloseexec only when needed
Get rid of the postrandom script.  It was born in a time when the
random script ran before filesystems were mounted, which is no
longer the case.

In random_start(), immediately delete each file that is fed into
/dev/random, and recreate the default entropy file immediately
after reading and deleting it.  The logic used in random_stop()
to determine which file to write to should probably be factored
out and used here as well.
Restore the auto-reseed logic, but move it to a much later point,
immediately before kick_init.

Approved by:	so (self)
filedesc: tidy up fdcheckstd

No functional changes.
NG_NODE_NAME(node) is always not NULL. Use correct macro.

Submitted by:	Dmitry Luhtionov <dmitryluhtionov gmail.com>