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

MFC r264573+264608+264609:

Sync with OpenBSD.

MFC r259058,r259060:

Remove -q from usage.

Document -q and --quiet as discouraged compatibility option.

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

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

Make definition match declaration

Approved by: cperciva
MFC after: 3 days

Fix world after byacc import:
- old yacc(1) use to magicially append stdlib.h, while new one don't
- new yacc(1) do declare yyparse by itself, fix redundant declaration of
'yyparse'

Approved by: des (mentor)

- Fix an erroneous invocation of the editline.
- Fix wrong scaling in the bc.library.
- Let length(0.000) conform to what gnu bc does.

PR: bin/159227
Submitted by: AIDA Shinra <shinra at j10n dot org>

Use libedit when interacting with tty, which provided history
functionality, etc. as did by GNU bc.

This also fixes an issue where BSDL bc can not handle very long
line.

Reported by: imp
Reviewed by: imp

- style(9)

Approved by: delphij (mentor)

- Remove --debug option and intentionally undocument -d, which is only
kept for compatibility with 4.4BSD behavior.
- Sync SYNOPSIS with usage().
- Use an alternative way to represent short and long options which have
same semantics.

Reviewed by: gabor

Replace GNU bc/dc with BSDL versions ported from OpenBSD. They have a good
compatibility level with the GNU counterparts and have shown to be mature
enough. For now, the GNU versions aren't removed from the tree, just detached
from the build.

Sponsored by: Google Summer of Code 2008
Portbuild run by: erwin
Approved by: delphij