Eliminate unnecessary references to pte.h internals by using the standard
pmap_kenter_temporary() to map pages while dumping.

Submitted by:	Svatopluk Kraus <onwahe@gmail.com>,
		Michal Meloun <meloun@miracle.cz>
Rename ip4_def_policy variable to def_policy. It is used by both IPv4 and
IPv6. Initialize it only once in def_policy_init(). Remove its
initialization from key_init() and make it static.

Remove several fields from struct secpolicy:
* lock - it isn't so useful having mutex in the structure, but the only
  thing we do with it is initialization and destroying.
* state - it has only two values - DEAD and ALIVE. Instead of take a lock
  and change the state to DEAD, then take lock again in GC function and
  delete policy from the chain - keep in the chain only ALIVE policies.
* scangen - it was used in GC function to protect from sending several
  SADB_SPDEXPIRE messages for one SPD entry. Now we don't keep DEAD entries
  in the chain and there is no need to have scangen variable.

Use TAILQ to implement SPD entries chain. Use rmlock to protect access
to SPD entries chain. Protect all SP lookup with RLOCK, and use WLOCK
when we are inserting (or removing) SP entry in the chain.

Instead of using pattern "LOCK(); refcnt++; UNLOCK();", use refcount(9)
API to implement refcounting in SPD. Merge code from key_delsp() and
_key_delsp() into _key_freesp(). And use KEY_FREESP() macro in all cases
when we want to release reference or just delete SP entry.

Obtained from:	Yandex LLC
Sponsored by:	Yandex LLC
Build gperf before gcc

The ARM image builds build the in-tree gcc in order to build u-boot
and gperf is needed to build gcc, but is no longer installed on archs
that use clang.

Invoking the make targets as separate steps is done to work around
a build failure which is not yet fully understood.

Reviewed by:	gjb, imp
Sponsored by:	The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D1317
Cleanup up ARM *frame structures...

 - Eliminate unused irqframe
 - Eliminate unused saframe
 - Instead of splitting r4-sp storage between the stack and switchframe,
   just put all the registers in switchframe and eliminate the un_32 struct.

Submitted by:	Svatopluk Kraus <onwahe@gmail.com>,
		Michal Meloun <meloun@miracle.cz>
Display the correct value for cache Level of Coherency.  Like the other
levels being displayed here, its value needs a +1 adjustment.
Modify vop_stdadvlock{async}() so that it only
locks/unlocks the vnode and does a VOP_GETATTR()
for the SEEK_END case. This is safe to do, since
lf_advlock{async}() only uses the size argument
for the SEEK_END case.
The NFSv4 server needs this when
vfs.nfsd.enable_locallocks!=0 since locking the
vnode results in a LOR that can cause a deadlock
for the nfsd threads.

Reviewed by:	kib
MFC after:	1 week