bug#29872: 26.0.90; `man' output encoding, hyphen chars

[Drew Adams <drew.adams@oracle.com>]

1. emacs -Q
2. load library cygwin-mount.el
3. load library setup-cygwin.el
4. M-x man RET find RET

The two libraries are on Emacs Wiki:
https://www.emacswiki.org/emacs?action=elisp-area;context=0

The `man' output has (presumably) end-of-line hyphens that are not shown
as such, perhaps because of the buffer encoding.  This is what is
present, for example:

 This  manual page documents the GNU version of find.  GNU find searches
 the directory tree rooted at each given file  name  by  evaluating  the
 given  expression  from left to right, according to the rules of preceâ€
 dence (see section OPERATORS), until the outcome  is  known  (the  left

(`report-emacs-bug' would not let me send this message with the above
text, so I've removed the character at the end of the line (after `â€'),
which is displayed as \220 (but a single character), so I could send the
msg.)

After "prece" there are these characters (from `C-u C-x ='):

LATIN SMALL LETTER A WITH CIRCUMFLEX
EURO SIGN
3fff90 (displayed as \220)

The charset is apparently windows-1252 (from `C-u C-x =').

Is this an Emacs bug, or is something different needed in, say,
setup-cygwin.el?  Currently, this code is in that library:

;;; Use Unix-style line endings.
;; Per Eli Z. http://debbugs.gnu.org/cgi/bugreport.cgi?bug=21780#40:
;;
;; $$$$$$ (setq-default buffer-file-coding-system 'undecided-unix)
(setq-default buffer-file-coding-system
              (coding-system-change-eol-conversion
                (default-value 'buffer-file-coding-system)
                'unix))
and this:

(setq process-coding-system-alist
      (cons '("bash" . (raw-text-dos . raw-text-unix))
             process-coding-system-alist))

I do not see this problem prior to this pretest build (e.g. with Emacs
24.5 or 25.3.1).  I do see the problem also with this Emacs 27 build:

 GNU Emacs 27.0.50 (build 4, x86_64-w64-mingw32) of 2017-12-21


In GNU Emacs 26.0.90 (build 3, x86_64-w64-mingw32)
 of 2017-10-13 built on LAPHROAIG
Repository revision: 906224eba147bdfc0514090064e8e8f53160f1d4
Windowing system distributor 'Microsoft Corp.', version 6.1.7601
Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.
Loading d:/usr/drew/drews-lisp-20/contrib/cygwin-mount.el (source)...done
Loading d:/usr/drew/drews-lisp-20/setup-cygwin.el (source)...done
Invoking man find in the background
find man page formatted
Type C-x 1 to delete the help window, C-M-v to scroll help.
Char: â (226, #o342, #xe2, file #xE2) point=477 of 75478 (1%) column=77
mwheel-scroll: Beginning of buffer [3 times]
Configured using:
 'configure --without-dbus --host=x86_64-w64-mingw32
 --without-compress-install 'CFLAGS=-O2 -static -g3''

Configured features:
XPM JPEG TIFF GIF PNG RSVG SOUND NOTIFY ACL GNUTLS LIBXML2 ZLIB
TOOLKIT_SCROLL_BARS

Important settings:
  value of $LANG: ENU
  locale-coding-system: cp1252

Major mode: Man

Minor modes in effect:
  tooltip-mode: t
  global-eldoc-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  tool-bar-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  buffer-read-only: t
  line-number-mode: t
  transient-mark-mode: t

Load-path shadows:
None found.

Features:
(shadow sort mail-extr emacsbug message rmc puny seq byte-opt gv
bytecomp byte-compile cconv format-spec rfc822 mml mml-sec
password-cache epa derived epg epg-config gnus-util rmail rmail-loaddefs
mm-decode mm-bodies mm-encode mail-parse rfc2231 mailabbrev gmm-utils
mailheader sendmail rfc2047 rfc2045 ietf-drums mm-util mail-prsvr
mail-utils cl-seq pp wid-edit descr-text help-mode tabify imenu man
easymenu cl-loaddefs cl-lib setup-cygwin cygwin-mount ange-ftp comint
ansi-color ring dired dired-loaddefs elec-pair time-date mule-util
tooltip eldoc electric uniquify ediff-hook vc-hooks lisp-float-type
mwheel dos-w32 ls-lisp disp-table term/w32-win w32-win w32-vars
term/common-win tool-bar dnd fontset image regexp-opt fringe
tabulated-list replace newcomment text-mode elisp-mode lisp-mode
prog-mode register page menu-bar rfn-eshadow isearch timer select
scroll-bar mouse jit-lock font-lock syntax facemenu font-core
term/tty-colors frame cl-generic cham georgian utf-8-lang misc-lang
vietnamese tibetan thai tai-viet lao korean japanese eucjp-ms cp51932
hebrew greek romanian slovak czech european ethiopic indian cyrillic
chinese composite charscript charprop case-table epa-hook jka-cmpr-hook
help simple abbrev obarray minibuffer cl-preloaded nadvice loaddefs
button faces cus-face macroexp files text-properties overlay sha1 md5
base64 format env code-pages mule custom widget hashtable-print-readable
backquote w32notify w32 multi-tty make-network-process emacs)

Memory information:
((conses 16 159308 20379)
 (symbols 56 33242 1)
 (miscs 48 101 150)
 (strings 32 88693 1858)
 (string-bytes 1 2015171)
 (vectors 16 22521)
 (vector-slots 8 1548032 220308)
 (floats 8 57 295)
 (intervals 56 17867 9)
 (buffers 992 14))