bug#12756: 24.2; woman.el vs adaptive-fill-mode hanging indent

[Kevin Ryde]

With the file percent.1 below and an 80-column screen the file percent.1
below processed with

    M-x woman-find-file percent.1

gives

    %%%%Some percents  one two three  four five six  seven eight
        nine ten eleven twelve thirteen fourteen fifteen.

Where I expected

    %%%%Some percents  one two three  four five six  seven eight
    nine ten eleven twelve thirteen fourteen fifteen.

It seems woman.el uses fill-region-as-paragraph and that
adaptive-fill-mode, which is t by default, causes the "%"s in the input
to become a fill prefix.  I think that shouldn't be done, that instead
woman.el should control all indentation.

It seems this only affects roff source where the paragraph flowed is a
single line of the input.  You can make a very long input line to see
multiple hanging lines in the output.  Various other prefix characters
in adaptive-fill-regexp are affected similarly, eg "#" instead of "%".

I get some joy from forcing adaptive-fill-mode off in
woman-decode-region.

2012-10-27  Kevin Ryde  <user42@zip.com.au>

        * woman.el (woman-decode-region): Let-bind adaptive-fill-mode nil so a
        paragraph consisting of a single long input line "%%Foo ..." doesn't
        have "%" treated as a hanging indent.

percent.1
Description: Text document

woman.el.adaptive-fill.diff
Description: Text Data

In GNU Emacs 24.2.1 (i486-pc-linux-gnu, GTK+ Version 2.24.10)
 of 2012-09-10 on biber, modified by Debian
Windowing system distributor `The X.Org Foundation', version 11.0.10707000
Configured using:
 `configure '--build' 'i486-linux-gnu' '--build' 'i486-linux-gnu'
 '--prefix=/usr' '--sharedstatedir=/var/lib' '--libexecdir=/usr/lib'
 '--localstatedir=/var/lib' '--infodir=/usr/share/info'
 '--mandir=/usr/share/man' '--with-pop=yes'
 
'--enable-locallisppath=/etc/emacs24:/etc/emacs:/usr/local/share/emacs/24.2/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/24.2/site-lisp:/usr/share/emacs/site-lisp'
 '--with-crt-dir=/usr/lib/i386-linux-gnu' '--with-x=yes'
 '--with-x-toolkit=gtk' '--with-toolkit-scroll-bars'
 'build_alias=i486-linux-gnu' 'CFLAGS=-g -O2 -fstack-protector
 --param=ssp-buffer-size=4 -Wformat -Werror=format-security -Wall'
 'CPPFLAGS=-D_FORTIFY_SOURCE=2''

Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: nil
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: en_AU
  value of $XMODIFIERS: nil
  locale-coding-system: iso-latin-1-unix
  default enable-multibyte-characters: t