Compile mp.w

Hello,

I'm the author of this question:
https://tex.stackexchange.com/questions/763896/how-to-compile-the-file-mp-w

I cloned the repository https://gitlab.lisn.upsaclay.fr/texlive/metapost/ and try to compile the file source\texk\web2c\mplibdir\mp.w with cweave like this:

$ pwd
/metapost/source/texk/web2c/mplibdir
$ cweave mp.w
$ pdftex mp.tex
I got a error message:

! Missing $ inserted.
<inserted text>
                 $
<to be read again>
                    _
<argument> \#define MPOST_
                           DEBUG_ENVELOPE
\C #1->\5\5\quad $/\ast \,${\cmntfont #1
                                         }$\,\ast /$
l.158 \M{5}\B\C{\#define MPOST_DEBUG_ENVELOPE }
                                                \6

The answer is accepted, so I think it's a bug in mp.w. If it's a bug, could you fix it in next release?

Best Wishes
Hong-Phuc Bui