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

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

Renumber clauses to reduce diffs to other versions

NetBSD, OpenBSD, and Android's Bionic number the clauses 1 through 3,
so follow suit to make comparison easier.

POSIX mandates that swab do nothing when len < 0

PR: kern/140690
Submitted by: Jeremy Huddleston <jeremyhu@apple.com>
Approved by: cperciva
MFC after: 2 weeks

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

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

According to the information on:
http://www.opengroup.org/onlinepubs/009695399/functions/swab.html
the prototype for swab() should be in <unistd.h> and not in <string.h>.
Move it, and update to match SUS. Leave the prototype in string.h for
now, for backwards compat.

PR: 74751
Submitted by: Craig Rodrigues <rodrigc@crodrigues.org>
Discussed with: das

- Convert the function definition to declare its arguments
in the ANSI-C format.
- Change the code a bit to hopefully save some cycles.
I.e. (simplified) change

a = b + 1;
while (--b & 0x7)
/* ... */
to
a = b;
for (; b & 0x7; b--)
/* ... */
and
while (--a >= 0)
/* ... */
to
for (; a > 0; a--)
/* ... */
- Equip two function arguments of swab() with the 'restrict'
type qualifier in form of the '__restrict' macro. This is
specified by POSIX.1-2001.

Remove 'register' keyword.

rcsid[]->__FBSDID

Make the rcsid and FreeBSD IDs more sane in the wcs* and wmem* files.
Do the same for the non-wcs*/wmem* files while I'm here.

This commit was generated by cvs2svn to compensate for changes in r1573,
which included commits to RCS files with non-trunk default branches.

BSD 4.4 Lite Lib Sources