Amend r263891, by making clang default to DWARF2 debug info format for
all FreeBSD versions, not just 10.x and earlier.  Apparently too many
people seem to have trouble with post-1993 formats.

Also remove the related notes about messing with kernel configuration
files from UPDATING, which are now superfluous.

Requested by:	many
MFC after:	3 days
Before calling mmap() on a shared library's text and data sections, rtld
first calls mmap() with the arguments PROT_NONE and MAP_ANON to reserve a
single, contiguous range of virtual addresses for the entire shared library.
Later, rtld calls mmap() with the the shared library's file descriptor
and the argument MAP_FIXED to place the text and data sections within the
reserved range.  The rationale for mapping shared libraries in this way is
explained in the commit message for Revision 190885.  However, this approach
does have an unintended, negative consequence.  Since the first call to
mmap() specifies MAP_ANON and not the shared library's file descriptor, the
kernel has no idea what alignment the vm object backing the file prefers.
As a result, the reserved range's alignment is unlikely to be the same as
the vm object's, and so mapping with superpages becomes impossible.  To
address this problem, this revision adds the argument MAP_ALIGNED_SUPER to
the first call to mmap() if the text section is larger than the smallest
superpage size.

To determine if the text section is larger than the smallest superpage
size, rtld must always fetch the page size information.  As a result, the
private code for fetching the base page size in rtld's builtin malloc is
redundant.  Eliminate it.  Requested by: kib

Tested by:	zbb (on arm)
Reviewed by:	kib (an earlier version)
Discussed with:	jhb
Account for the "plus 1" encoding of the CPUID Function 4 reported
core per package and cache sharing values.

Approved by:	grehan (co-mentor)
Improve use of socket buffer upcalls.

Use soreadable()/sowriteable() in socket upcalls to avoid extra wakeups
until we have enough data to read or space to write.

Increase partial receive len from 1K to 128K to not wake up on every
received packet.

This significantly reduces locks congestion and CPU usage and improves
throughput for large I/Os on NICs without TSO and LRO.

Reviewed by:	trasz
Sponsored by:	iXsystems, Inc.
mdoc and spelling cleanup.

MFC after:	3 days
Update the llvm/clang patch for r264345.
The tw_pcbrele() function does not need the global timewait lock.

Submitted by:	Julien Charbon
Suggested by:	glebius
There is no need to save and restore the host's return address in the
'struct vmxctx'. It is preserved on the host stack across a guest entry
and exit and just restoring the host's '%rsp' is sufficient.

Pointed out by:	grehan@
Fix insta-panic on assert of unlocked periph mtx in ciss(4) when
logical volume state changes.

Currently, I view this as a critical fix for users and will MFC this rapidly as
my testing has shown data loss when the disk is failed by removing it when
under some amount of write activity and this code panics the box.

Reviewed by:	mav@ scottl@
MFC after:	3 days
Sponsored by:	Yahoo! Inc.
Remove unused val argument value from SYSCTL_INT() calls.
Some whitespace and style fixes.

Submitted by:	bde
MFV r258194-264360: nc(1) from OpenBSD 5.5.

MFC after:	2 weeks
Remove stray .Nm macro.

MFC after:	3 days
Update the SDT(9) examples to reflect the removal of the sname parameter
in r258622.

MFC after:	3 days
Properly release the in6_multi lock.

MFC after:	1 week
Sponsored by:	Yandex LLC
Introduce RANLIBFLAGS to mirror ARFLAGS and add -D to both.  This sets
all timestamps in static libraries to 0 so that consecutive builds
from the same source, even on different machines, produce identical
libraries.

MFC after:	3 weeks
Remove the names of the build host and user and the build date.  This
still leaves the host OS and version, but these are harder to remove.

MFC after:	3 weeks
Align and round the partitionable disk space to 4K by default.
Since this would also apply when recovering, make sure not to
align or round when that would have a partition fall outside
the partitionable area.
mdoc and language improvements.

MFC after:	1 week
Use proper MFSNAMELEN for fs type.

MFC after:	2 weeks
Reviewed by:	rodrigc
Also spotted by:ambrisko