MFC r343105: libedit: Avoid out of bounds read in 'bind' command

This is CVS revision 1.31 from NetBSD lib/libedit/chartype.c:
Make sure that argv is NULL terminated since functions like tty_stty rely
on it to be so (Gerry Swinslow)

This broke when the wide-character support was enabled in libedit. The
conversion from multibyte to wide-character did not supply the apparently
expected terminating NULL in the new argv array.

PR: 233343

MFC r340933:

libedit: improve multibyte support

Until this commit libedit only supported UTF-8 for multibyte charset
Improve it to support other multibyte charsets

Tested with eucJP and SJIS charsets.
Note that this change as been review and committed in upstream libedit
as well via christos@NetBSD

Submitted by: naito.yuichiro _at_ gmail.com
Reviewed by: bapt, pfg, yuripv, 0mp
Differential Revision: https://reviews.freebsd.org/D17903

MFC r323547, r323598:
libedit: add missing bracket.

We never hit this because we always build with widechar support.
Raise the warning level to 3.

MFC r312997, r313002:
Re-import libedit 2016-02-27 and update libedit with changes from NetBSD's
2016-03-21.

Obtained from: NetBSD

Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

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

Revert r296175
Undo update of libedit 2016-02-27

Something in libedit appears to be causing breakage in lldb38.
The changes are not generally huge but they are suficient to
to justify reverting for now.

Reported by: novel, bapt

MFV r296159
Sync our libedit with NetBSD's libedit 2016-02-27.

Obtained from: NetBSD

Synchronize libedit with NetBSD

It incorporates and fixes our patches to get el_gets return the proper count of
characters in unicode mode.

Synchronize libedit with NetBSD and activate UTF-8 support [1]

Differences with NetBSD
Reapply our local patches on top of it
Fix Unicode environement detection
Fix reading a line in unicode environment.
It allows /bin/sh to works in UTF-8 envs

Differential Revision: https://reviews.freebsd.org/D1455
Reviewed by: jilles, pfg
Obtained from: NetBSD [1]
MFC after: 1 month
Relnotes: yes