Hi Laurent,
I submitted a bug upstream about the source for this tool not being included in the upstream tarball in the first place.
This was due to the fact that when it was added to Mesa, it wasn't included in the Autotools build system, only the meson build system. All the tarballs are made using Autotools (even upstream).
Unfortunately this patch didn't make it into Mesa 18.1.1.
Also, the fix provided upstream has been to simply add the files to EXTRA_DIST, which means they'll make it into the tarball, but they're not compiled by Autotools.
I would suggest logging a bug upstream against this to have the necessary tool built by Autotools, as the Debian builds use Autotools as far as I know. Feel free to reference my bug.
In the meantime, if you need this tool for debugging, I would suggest you grab the Debian source using `apt-get source` and try building it yourself.
Note: Every time I've tried to add meson/ninja to my system to do a build, it wanted to remove all the Debian build helper tools, which doesn't help any.
PS: Mesa 18.1.2 upstream is due for release today (15th June), so I would not expect to see any changes in this behaviour till Mesa 18.1.3 at the earliest (29th June). This is based on the release calendar currently at
https://mesa.freedesktop.org/release-calendar.html