maxima-doc broken in bionic

after upgrading my latop to ubuntu 18.04 LTS, although maxima, xmaxima, wxmaxima and maxima-doc were already installed no help pages were accessible in wxmaxima (and so xmaxima can't start) . reinstalling maxima, xmaxima, wxmaxima and maxima-doc doesn't solve the problem .

After some investigation (see the mailing list : https://sourceforge.net/p/maxima/mailman/message/36406550/ ) I discovered that the directory /usr/share/maxima/*.*.*/doc/ never exists after installation.

A work-around to solve the problem consist to install maxima-sage-doc and copy the help file system to maxima :

* install maxima-sage documentation package
sudo apt-get install maxima-sage-doc

* copy the doc/ directory for maxima-sage into the wxmaxima directory
sudo cp -R /usr/share/maxima-sage/5.39.0/doc/ /usr/share/maxima/5.41.0/

* now the html help files are readable in wxmaxima but to enable the
search in chapter and index you have to uncompress the corresponding gz
files in doc/html/ directory

cd /usr/share/maxima/5.41.0/doc/html
sudo gunzip contents.hhc.gz
sudo gunzip index.hhk.gz