Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Add section .note.GNU-stack for assembly files used by 386 and amd64.

Add missing END() macros, as per rev 184547 for amd64. The lack of these
is mostly harmless, but it does upset some of valgrind's functionality.

Per Regents of the University of Calfornia letter, remove advertising
clause.

# If I've done so improperly on a file, please let me know.

Eliminate superfluous memory access in memcpy(3)/memmove(3).

Obtained from: NetBSD
MFC after: 1 week

Fix style bugs I added in last commit.

Spotted by: bde

Modify bcopy (and memcpy/memmove) so that the length value is not
re-read from the stack mid copy. This may help mitigate the recent
Apache buffer overrun and future overruns of the sort.

Reviewed by: jdp
MFC after: 2 days

Standardize on our SCM ID style.

Merged with the 1996/11/12 NetBSD version:
- use a slightly less bogus copyright. This file was never contributed
to Berkeley. It still claims to be copright by the Regents.
- use <machine/asm.h> instead of "DEFS.h".
- use RCSID($Id$) instead of explicit assembly code and messy ifdefs.
The rcsid won't be put into the object file until we make RCSID()
non-null. NetBSD uses a LIBC_SCCS ifdef here. We used a LIBC_RCS
instead, but I want RCSID() to be controlled directly by LIBC_RCS
(actually by LIB_RCS). This is the only difference with the NetBSD
version.
- added ifdefs to support generation of memcpy() and memmove(). The
other changes are "while I'm here" to get this.
- improved style of the copy backwards case.

Revert $FreeBSD$ to $Id$

Make the long-awaited change from $Id$ to $FreeBSD$

This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.

Boy, I'm glad we're not using sup anymore. This update would have been
insane otherwise.

Be smarter about handling overlapped copies and only go backwards if it
is really necessary. Going backwards on a P6 is much slower than forwards
and it's a little slower on a P5. Also moved the count mask and 'std'
down a few lines - it's a couple percent faster this way on a P5.

First round of changes to clean up the RCSID mess in libc:

1) Changed LIB_SCCS and SYSLIB_SCCS to LIB_RCS and SYSLIB_RCS.
2) Changed sccsid[] variables to rcsid[]
3) Moved all RCSID strings into .text
4) Converted all SCCSID's to RCS $Id$'s
5) Added missing $Id$'s after copyright.

First crack at making libc work with the new make macros. It compiles on
my machine, and a simple static (genassym) and shared (sysctl) executable
both work. Still to be done: RPCand YP merge.