Hi, I had a look: - sagemath build-depends on cython3 - /usr/bin/cython is in cython - /usr/bin/cython3 is in cython3
so I see two ways out : (1) change the b-dep to cython (from cython3) [and cython-dbg from cython3-dbg, I guess] ; (2) make so cython is called as cython3. I can't give it a try before at least a week, so if someone wants to dive in... JP