typos in comments; from Pedro Giffuni (FreeBSD) via Christos Zoulas (NetBSD)

delete the "private" and "public" preprocessor macros, just use standard C;
OK martijn@

Clean up chartype.h:

* not used in tokenizer.c
* only use it for !NARROWCHAR
* no need for underscores before ct_{de,en}code_string()
* make the conversion buffer resize function private

OK martijn@

get rid of the non-standard data type "Char" in almost all files;
ok martijn@

Move wrapper macros to the two files actually needing them:
FUNW, Strlen, Strdup, Strcmp, Strncmp, Strncpy, Strncat -> history.c
Strchr, tok_strdup -> tokenizer.c
FUN, TYPE, STR -> both of these files

OK martijn@

Also proofread by Christian Heckendorf <mbie at ulmus dot me>
who reported some whitespace issues in parse.c.

Delete 26 wrapper macros and two wrapper functions that are no
longer needed now that we always compile with wide character support,
reducing code obfuscation.

OK czarkoff@ martijn@.
Diff also proofread by Christian Heckendorf <mbie at ulmus dot me>.

Always compile with WIDECHAR on and delete that preprocessor switch.
OK martijn@.
Diff also proofread by Christian Heckendorf <mbie at ulmus dot me>.

format string fixes in debug code;
committing right away because this code is not even compiled by default

Christos Zoulas just rescinded clauses 3 & 4 of his licenses, see
NetBSD chartype.c rev. 1.23, chartype.h rev. 1.25, eln.c rev. 1.28.
No code change.

Make the read_char() function always take a wchar_t * argument.

On first sight, it might look as if this required a bump because
it seems to change the public type el_rfunc_t. But we only compile
with WIDECHAR, and in that case, there is no change in the interface.

This also simplifies some logic by getting rid of the NARROW_READ flag
which was broken anyway.

OK czarkoff@

Cleanup of standard header inclusion:

1. Add the missing <errno.h> to sig.c.
2. Do not include standard headers from private headers "chared.h"
and "el.h", include them directly where needed.
3. Delete a few needless inclusions of <ctype.h>.
4. Sort the standard headers.
5. Delete _GNU_SOURCE weirdness from histedit.h, that file doesn't even
need the access to wcsdup(3) mentioned in the comment.
6. Delete some trailing blanks and blanks before tabs.

OK czarkoff@

Delete the useless Int datatype and always use the standard wint_t
directly. This is not a problem because <wchar_t> is required all
over the place anyway, even when WIDECHAR is not defined.
No functional change except that it fixes a few printf(3)
format string issues, %c vs. %lc.
OK czarkoff@

Get rid of "#ifdef WIDECHAR" and one goto in read_char(),
making the code more readable. Instead, provide an mbrtowc(3)
replacement function in chartype.[hc], files that encapsulate
such system dependencies anyway. No functional change.
OK czarkoff@

Fix the public interface function el_getc(3).
On OpenBSD, the effects are to set the return argument to the NUL byte
in case of a read failure (for robustness) and to properly set errno
when the character is out of range and cannot be stored in a byte.
Once we enable UTF-8, this will be needed to avoid returning bogus
bytes for valid Unicode characters.
On systems where the internal representation of wchar_t doesn't
match UCS-4, breakage was potentially even worse.
OK czarkoff@.

Fix the CHARSET_IS_UTF8 case in read_char().
For now, this mainly help programs explicitly using
wide-character functions like el_wgetc(3) and el_wgets(3).

1. After reading an invalid byte sequence, do not throw away additional
valid bytes; fix by me using mbrtowc(3), obsoleting utf8_islead().
2. When read(2) returns EOF, return that information to the caller,
do not prod on and potentially access garbage data in the buffer;
from Linas Vepstas via NetBSD read.c rev. 1.70 2013/05/27.
3. After read__fixio() failure, restore errno to the one set by read();
from Steffen Nurpmeso via NetBSD read.c rev. 1.68 2012/09/10.
4. After read__fixio() success, restore errno to the initial state
upon function entry; fix by me.

OK czarkoff@. Also committed to NetBSD.

Remove non-exposed malloc/realloc/free wrappers, and then substitute
reallocarray() where it helps.
ok doug

Enable wide character functions in libedit (not the other libe*t).

ok stsp deraadt

sync with upstream, retaining local modifications.

ok nicm@

Make wcwidth() callers cope with -1 return value. Doesn't affect the build yet.
ok nicm

Update libedit to bring it into sync with the latest version from NetBSD.

ok deraadt