Copy stable/10@r272459 to releng/10.1 as part of
the 10.1-RELEASE process.

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

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

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

Revert most part of 200420 as requested, as more review and polish is
needed.

Remove unneeded header includes from usr.bin/ except contributed code.

Tested with: make universe

getopt.c is public domain. Add a comment to that effect.

Remove confusing README.

PR: bin/98911
Submitted by: Jason McIntyre <jmc at kerhand dot co dot uk>
Obtained from: OpenBSD
MFC after: 3 days

ANSIify function definitions.
Add some constness to avoid some warnings.
Remove use register keyword.
Deal with missing/unneeded extern/prototypes.
Some minor type changes/casts to avoid warnings.

Reviewed by: md5

Consistently use FBSDID

Minor nit; return(foo) from main rather than exit(foo).

Warns cleanup (just make main return an int).

Include missing header files which define functions for which gcc has
builtins (e.g., exit, strcmp).

getopt and friends are declared in <unistd.h>
getopt returns -1 not EOF.

Back out part of previous commit.

Arguments with whitespaces are easy to fix, but in combination with
shell metachars that should not be evaluated it is very hard, probably
impossible to fix without going to a line-oriented solution.

Next time I will believe Henry Spencer when he says "this looks easy
to fix but isn't".

1) Fix the case where a shellscript using getopt is called with a
parameter that has space in it, both in getopt.c and in the manpage
example.

2) Fix the example in the manpage. The set(1) command is required to
return 0 (POSIX 1003.2, section 3.14.11), so you can't test for
getopt's exit status like the example did:

#! /bin/sh
set -- `getopt abo: $*`
if test $? != 0 # wrong, tests for set's exit status, which is
# always zero, no for getopt(1)'s.

Fixes PR bin/5845, which thought it was getopt's fault, but in fact
the manpage was wrong.

I also updated the example to be more useful and updated the BUGS
section.

PR: bin/5845

compare return value from getopt against -1 rather than EOF, per the final
posix standard on the topic.

Added getopt(1) from NetBSD