bison-mode complains: Cannot open load file

[mickbert]

I am really a newbie in such field: I downloaded bison-mode.el from [1], 
copied it into ~/.emacs.d/lisp (where I have few other modules I use 
daily), and added in ~/.emacs the line:

  (autoload 'bison-mode "bison-mode" "Major mode for editing Markdown 
files" t)

When I issue the command "M-x bison-mode", it answers with the message

  "Cannot open load file: No such file or directory, make-regexp"

Do you have any suggestion?
--
Mick

[1] https://www.emacswiki.org/emacs/BisonMode