MFC	r258081, r258138, r258143, r258179, r258157, r258204, r258205,
	r258206, r258207, r258321

This is a series of commits inspired on Google's gcc-4.2.1 for
Android that were taken from the gcc pre-4.3 under the GPLv2.

gcc: Backport fixes for -W parentheses in C++
	This fixes GCC 19564.
gcc: merge rs6000 change from FSF pre-gcc43
	Don't set MASK_PPC_GFXOPT for 8540 or 8548.
Merge vrp-tree fix from gcc-4.3
	Fix missed conversion from / to >> (GCC PR32521)
Merge in GCCr120505 to include definition of TREE_OVERFLOW_P
gcc: warn about integer overflow in constant expressions in the C++
frontend.
gcc: Add a new option -Wvla to warn variable length array.
libcpp: preprocessor speedup patches from upstream gcc.
gcc: add femit-struct-debug support to reduce Reduce dwarf debug size
gcc: Fix postreload-gcse treatment of call-clobbered registers.
gcc: Record some previous commits in the ChangeLog.gcc43 file.

Tested by:	danfe
MFC r258573:

Removes strict-aliasing warnings from newer GCC in tcpdump.
MFC	r259920:

gcc: Implement -Wmost for compatibility with clang.

This is equivalent to -Wall -Wno-parentheses.

Obtained from:	Apple GCC 4.2 - 5531
MFC	r259666, r259696:

gcc: warnings from -Wformat-security

Obtained from:	Apple GCC 4.2 - 5646 (Radar 5764921)
MFC r259197:
Do not DELAY() for P-state transition unless we want to see the result.

Intel manual says: "If a transition is already in progress, transition to
a new value will subsequently take effect. Reads of IA32_PERF_CTL determine
the last targeted operating point."  So seems it should be fine to just
trigger wanted transition and go.  Linux does the same.
MFC 197775,197777-197779,197781,197794,243152,243313,255478:
First cut at implementing SOCK_SEQPACKET support for UNIX (local) domain
sockets.  This allows for reliable bi-directional datagram communication
over UNIX domain sockets, in contrast to SOCK_DGRAM (M:N, unreliable) or
SOCK_STERAM (bi-directional bytestream).  Largely, this reuses existing
UNIX domain socket code.  This allows applications requiring record-
oriented semantics to do so reliably via local IPC.
MFC r259921,259950:

Provide the manual page for aio_fsync(2).
MFC r260636:

Fix bsnmpd remote denial of service vulnerability.

Reported by:	dinoex
Submitted by:	harti
Security:	FreeBSD-SA-14:01.bsnmpd
Security:	CVE-2014-1452
MFC r260637:

Disable 'monitor' feature in ntpd by default.

Security:	FreeBSD-SA-14:02.ntpd
Approved by:	so
On stable/8 and stable/9, disable hardware random number generators
by default.  This is a direct commit to stable/ branches because
HEAD and stable/10 have superior implementation of random device.

Approved by:	so
MFC r259951 (kib):

Do not coalesce stack entry. Pass MAP_STACK_GROWS_DOWN and
MAP_STACK_GROWS_UP flags to vm_map_insert() from vm_map_stack()
Fix  BIND remote denial of service vulnerability.

Security:	FreeBSD-SA-14:04.bind
Security:	CVE-2014-0591
MFC r253821,254753,256259

MFV r253783: 3834 incremental replication of 'holey' file systems is
slow

MFV r254747:4047 panic from dbuf_free_range() from dmu_free_object()
while doing zfs receive

MFV r255257: 4082 zfs receive gets EFBIG from dmu_tx_hold_free()
MFC r258351: fsx: new option to disable msync(MS_SYNC) after each write
MFC r258352: fsx: add an option to randomly call msync(MS_INVALIDATE)
MFC r258638,258642: expose zfs_flags as debug.zfs_flags r/w tunable and sysctl

Sponsored by:	HybridCluster
MFC r258647: zfsboottest: properly specify a library dependency
MFC r258628: opensolaris taskq: some cosmetic changes
MFC r258630: 734 taskq_dispatch_prealloc() desired
MFC r258743: drop ZUT_OBJ