sleep(1): minor markup tweaks

Sort sections.

While cute, the previous version is not really safe.
After all, a system might want to sleep for several
thousand years on a spaceship headed to a distant
solar system...

So, remove the pause() code, deal with limits on the
range (it is just an int) that can be passed to sleep()
by looping, and do a much better job of checking for
out of range input values.

With this change sleep(1) should work for durations
up to something more than 250 billion years. It
fails (at startup, with an error) if the requested
duration is beyond what can be handled.

Here no changes at all related to locales and arg
parsing. Still for another day.

Adjust the way the arg string is parsed in the "not entirely
integer" case, so we avoid adjusting the locale of sleep,
and generally be more reliable and simpler.

In addition, deal with weirdness in nanosleep() when the
interval gets long, by avoiding using it. In this version
when the sleep interval < 10000 seconds, we use nanosleep()
as before, for delays longer than that we use sleep() instead,
and ignore any fractional seconds.

We avoid overflow problems here by not bothering to sleep
at all for delays longer than 135 years (approx) and simply
pause() instead. That sleep never terminates in such a
case is unlikely to ever be observed.

This commit makes no decision on the question of whether
the arg should be interpreted in the locale of the user,
or always in the C locale. That is for another day.

branches: 1.24.4; 1.24.6;
Remove workaround for ancient HTML generation code.

Document the version sleep first appeared.
Bump date.

Improve wording.
From Snader_LB.

Bump date for SIGINFO.

add SIGINFO support; from freebsd:

when a SIGINFO is delivered, display the approximate remaining seconds.

- Cleanup for sleep.c:
+ mark two functions as static
+ remove case '?' in switch() before default
+ use return instead of exit() in main() function
+ use constants EXIT_SUCCESS/EXIT_FAILURE instead of 0/1

- In man sleep(1):
+ cleanup example

Patch submitted by Slava Semushin <php-coder@altlinux.ru> in private email.

Move UCB-licensed code from 4-clause to 3-clause licence.

Patches provided by Joel Baker in PR 22249, verified by myself.

Use shell glob expansion in the csh example, instead of ls with glob.
Reported by Jerry Peek <jpeek@jpeek.com>.

New policy: New sentences start on a new line.
Patches by Robert Elz <kre at munnari oz au>, with minimal changes by me.

Generate <>& symbolically. I'm avoiding .../dist/... directories for now.

Sort SEE ALSO.

For commands and utilities, use EXIT STATUS rather than RETURN VALUES as
appropriate (and documented in mdoc(7)).

Add 'RETURN VALUE' section header.

branches: 1.11.12;
- getopt returns -1 not EOF
- use .Nm appropriately

Make sleep handle non-integer values. Document the same, noting that
the extension is grotesquely non-portable.

As requested by Denny Gentry in pr-3914. He supplied some code, but I
used all my own code in the change, and wrote documentation for the
man page.

This is creeping featurism at its worst. I added it only because I
can't see a good reason for refusing. However, I'm disgusted with
myself for doing it anyway.

Use "utility" instead of "command". Modern definitions of these terms
are distinct (See POSIX.2 glossary).

A utility is a executable, script or shell builtin; while a command
can be any of those things plus lists, pipelines, compound commands
(if, for, while) and shell function definitions.

convert to new RCS id conventions.

Merge 4.4-Lite version.

Fix spelling errors.

localization & manpage update.

Add RCS indentifiers.

changed "Id" to "Header" for rcsids

added rcs ids to all files

branches: 1.1.1;
Initial revision