Salut Serge,
I’m not using the build-art script, but just the following.
(initial: git clone https://bitbucket.org/agriggio/art.git, to fetch the code).
Then:
cd art
git pull (# new code available?)
cmake -DCMAKE_BUILD_TYPE=Release
make -j5 (# for a four-core cpu)
sudo make install
Hope this helps.