bug#34017: 26.1; emacs-w3m no longer works

[Art Werschulz <agw@dsm.fordham.edu>]

When using vm to read mail in emacs, if the message has HTML mail, I get
the message
Inline text/html by emacs-w3m display failed: (wrong-type-argument stringp nil)
in the minibuffer.  Moreover, only the HTML source of the message
appears in the presentation buffer.

Note that this all worked up through last Friday.  I haven't changed my
emacs configuration since then, but we did upgrade from Fedora 28 to
Fedora 29.


In GNU Emacs 26.1 (build 1, x86_64-redhat-linux-gnu, GTK+ Version 3.23.2)
 of 2018-08-13 built on buildvm-13.phx2.fedoraproject.org
Windowing system distributor 'The X.Org Foundation', version 11.0.70000000
System Description:	Fedora release 29 (Twenty Nine)

Recent messages:
vm-run-command: "firefox" ("-remote" "openURL(https://emacs.stackexchange.com/users/253/dan)")
Sending URL to Mozilla Firefox... done
Sending URL to Mozilla Firebird...
vm-run-command: "firefox" ("-remote" "openURL(https://emacs.stackexchange.com/users/253/dan)")
Sending URL to Mozilla Firefox... done
Decoding MIME message... done
Sending URL to Mozilla Firebird...
vm-run-command: "firefox" ("-remote" "openURL(https://savannah.gnu.org/mail/?group=emacs)")
Sending URL to Mozilla Firefox... done
Auto-saving...

Configured using:
 'configure --build=x86_64-redhat-linux-gnu
 --host=x86_64-redhat-linux-gnu --program-prefix=
 --disable-dependency-tracking --prefix=/usr --exec-prefix=/usr
 --bindir=/usr/bin --sbindir=/usr/sbin --sysconfdir=/etc
 --datadir=/usr/share --includedir=/usr/include --libdir=/usr/lib64
 --libexecdir=/usr/libexec --localstatedir=/var
 --sharedstatedir=/var/lib --mandir=/usr/share/man
 --infodir=/usr/share/info --with-dbus --with-gif --with-jpeg --with-png
 --with-rsvg --with-tiff --with-xft --with-xpm --with-x-toolkit=gtk3
 --with-gpm=no --with-xwidgets --with-modules
 build_alias=x86_64-redhat-linux-gnu host_alias=x86_64-redhat-linux-gnu
 'CFLAGS=-DMAIL_USE_LOCKF -O2 -g -pipe -Wall -Werror=format-security
 -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -fexceptions
 -fstack-protector-strong -grecord-gcc-switches
 -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1
 -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -m64 -mtune=generic
 -fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection'
 LDFLAGS=-Wl,-z,relro
 PKG_CONFIG_PATH=:/usr/lib64/pkgconfig:/usr/share/pkgconfig'

Configured features:
XPM JPEG TIFF GIF PNG RSVG IMAGEMAGICK SOUND DBUS GSETTINGS NOTIFY ACL
LIBSELINUX GNUTLS LIBXML2 FREETYPE M17N_FLT LIBOTF XFT ZLIB
TOOLKIT_SCROLL_BARS GTK3 X11 MODULES THREADS XWIDGETS LCMS2

Important settings:
  value of $LC_ALL: C
  value of $LANG: en_US.UTF-8
  locale-coding-system: nil

Major mode: Messages

Minor modes in effect:
  auto-insert-mode: t
  display-time-mode: t
  which-function-mode: t
  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
  size-indication-mode: t
  column-number-mode: t
  line-number-mode: t
  auto-fill-function: do-auto-fill
  transient-mark-mode: t
  auto-fill-mode: 1

Load-path shadows:
/usr/share/emacs/site-lisp/rinari/util/jump/which-func hides /usr/share/emacs/26.1/lisp/progmodes/which-func
/usr/share/emacs/site-lisp/rinari/util/ruby-mode hides /usr/share/emacs/26.1/lisp/progmodes/ruby-mode
/u/sobolev/agw/elisp/hebrew hides /usr/share/emacs/26.1/lisp/language/hebrew

Features:
(shadow sort mail-extr warnings emacsbug help-mode cl-print debug
misearch multi-isearch vm-digest vm-delete message rmc puny format-spec
rfc822 mml mml-sec password-cache epa derived epg epg-config gnus-util
rmail rmail-loaddefs mm-decode mm-bodies mm-encode gmm-utils mailheader
flyspell ispell vm-edit mailalias vm-reply vm-sort longlines mail-parse
rfc2231 mailcap doc-view dired dired-loaddefs image-mode timezone
w3m-hist w3m-fb bookmark-w3m w3m-ems wid-edit w3m-ccl ccl w3m-favicon
w3m-image w3m-proc w3m-util vm-save tapestry easymenu vm-rfaddons
sendmail rfc2047 rfc2045 ietf-drums mm-util mail-prsvr mail-utils
vm-menu vm-window vm-toolbar vm-folder vm-mime vm-undo vm-summary
vm-mouse vm-page vm-motion vm-minibuf vm-message vm-misc vm-macro vm
elec-pair jka-compr autoinsert cus-start cus-load tempo edmacro kmacro
my-font-stuff mailabbrev gin-mode server time u-vm-color vm-autoloads
vm-vars vm-version preview-latex rinari advice cl jump inflections findr
ruby-compilation which-func imenu pcomplete inf-ruby compile comint
ansi-color ring ruby-mode clang-rename clang-include-fixer let-alist
json map seq byte-opt bytecomp byte-compile cconv clang-format cl-macs
gv xml cl-loaddefs cl-lib bbdb-loaddefs auto-loads tex-site time-date
mule-util tooltip eldoc electric uniquify ediff-hook vc-hooks
lisp-float-type mwheel term/x-win x-win term/common-win x-dnd 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 dbusbind inotify lcms2
dynamic-setting system-font-setting font-render-setting xwidget-internal
move-toolbar gtk x-toolkit x multi-tty make-network-process emacs)

Memory information:
((conses 16 247561 26882)
 (symbols 48 30193 1)
 (miscs 40 741 895)
 (strings 32 100565 4432)
 (string-bytes 1 2360720)
 (vectors 16 25419)
 (vector-slots 8 675835 24246)
 (floats 8 138 477)
 (intervals 56 3402 2261)
 (buffers 992 28))

-- 

-- 
Arthur G. Werschulz (http://www.dsm.fordham.edu/~agw)
Assoc. Chair for Undergrad Studies, Lincoln Center 
Dept of Computer and Information Sciences
Fordham University
LL610D 
(212) 636-6325