Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

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

MFC r232262 by tijl:

Copy amd64 _limits.h to x86 and merge with i386 _limits.h. Replace
amd64/i386/pc98 _limits.h with stubs.

MFC (part of) r235939 by obrien:

Consitently use "__LP64__".

Sponsored by: The FreeBSD Foundation

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

Fix types of some values in machine/_limits.h.

On some architectures UCHAR_MAX and USHRT_MAX had type unsigned int.
However, lacking integer suffixes for types smaller than int, their type
should correspond to that of an object of type unsigned char (or short)
when used in an expression with objects of type int. In that case unsigned
char (short) are promoted to int (i.e. signed) so the type of UCHAR_MAX and
USHRT_MAX should also be int.

Where MIN/MAX constants implicitly have the correct type the suffix has
been removed.

While here, correct some comments.

Reviewed by: bde
Approved by: kib (mentor)

Move MINSIGSTKSZ from <machine/signal.h> to <machine/_limits.h> and rename
it to __MINSIGSTKSZ. Define MINSIGSTKSZ in <sys/signal.h>.

This is done in order to use MINSIGSTKSZ for the macro PTHREAD_STACK_MIN
in <pthread.h> (soon <limits.h>) without having to include the whole
<sys/signal.h> header.

Discussed with: bde

Begin all license/copyright comments with /*-

Remove advertising clause from University of California Regent's license,
per letter dated July 22, 1999.

Approved by: core

Cosmetic and/or trivial sync up with i386.

Approved by: re (rwatson)

sys/sys/limits.h:

- Fix visibilty test for LONG_BIT and WORD_BIT. `#if defined(__FOO_VISIBLE)'
is alays wrong because __FOO_VISIBLE is always defined (to 0 for
invisibility).

sys/<arch>/include/limits.h
sys/<arch>/include/_limits.h:

- Style fixes.

Submitted by: bde
Reviewed by: bsdmike
Approved by: re (scottl)

Style fixes.
Remove DBL_DIG, DBL_MIN, DBL_MAX and their FLT_ counterparts, they
were marked for deprecation ever since SUSv1 at least.
Only define ULLONG_MIN/MAX and LLONG_MAX if long long type is
supported.
Restore a lost comment in MI _limits.h file and remove it from
sys/limits.h where it does not belong.

Add a new sys/limits.h file which in turn depends on machine/_limits.h
to get actual constant values. This is in preparation for machine/limits.h
retirement.

Discussed on: standards@
Submitted by: Craig Rodrigues <rodrigc@attbi.com> (*)
Modified by: kan

Correct typos, mostly s/ a / an / where appropriate. Some whitespace cleanup,
especially in troff files.

MB_LEN_MAX is not MD, move it to the MI limits.h.

Create a new header <machine/_stdint.h> for storing MD parts of
<stdint.h>. Previously, parts were defined in <machine/ansi.h> and
<machine/limits.h>. This resulted in two problems:
(1) Defining macros in <machine/ansi.h> gets in the way of that
header only defining types.
(2) Defining C99 limits in <machine/limits.h> adds pollution to
<limits.h>.

This is the start of the FreeBSD/x86_64 kernel.