Thanks for making the updates again.
It is just a tiny step from getting it accomplished. I ran the commands (install-info) in the elevated console but there are error messages that install-info cannot find the directories / files. Here are the outputs:
[...]
make[1]: Entering directory '/cygdrive/d/home/jwong/.emacs.d/packages/emacs-w3m/doc'
/bin/sh ../mkinstalldirs "c:/Program Files (x86)/GNU Emacs 24.5/share/info"
/usr/bin/install -c -m 644
emacs-w3m.info "c:/Program Files (x86)/GNU Emacs 24.5/share/info/
emacs-w3m.info"
/usr/bin/install -c -m 644
emacs-w3m-ja.info "c:/Program Files (x86)/GNU Emacs 24.5/share/info/
emacs-w3m-ja.info"
install-info --info-dir="c:/Program Files (x86)/GNU Emacs 24.5/share/info" "c:/Program Files (x86)/GNU Emacs 24.5/share/info/
emacs-w3m.info"
install-info: No such file or directory for /Program Files (x86)/GNU Emacs 24.5/share/info/
emacs-w3m.infoinstall-info --info-dir="c:/Program Files (x86)/GNU Emacs 24.5/share/info" "c:/Program Files (x86)/GNU Emacs 24.5/share/info/
emacs-w3m-ja.info"
install-info: No such file or directory for /Program Files (x86)/GNU Emacs 24.5/share/info/
emacs-w3m-ja.infomake[1]: Leaving directory '/cygdrive/d/home/jwong/.emacs.d/packages/emacs-w3m/doc'
$ install-info "/cygdrive/c/Program Files (x86)/GNU Emacs 24.5/share/info/
emacs-w3m.info"
install-info: No dir file specified; try --help for more information.
$ install-info "/cygdrive/c/Program Files (x86)/GNU Emacs 24.5/share/info/
emacs-w3m-ja.info"
install-info: No dir file specified; try --help for more information.