Add install_requires to setup.py/setup.cfg, or add pyproject.toml

[mkoeppe]

On a system with fplll installed, pip install fpylll fails because the distribution does not declare its Python build dependencies.

[malb]

We're using distutils which doesn't know install_requires and I dread adding more of these meta files to the toplevel directory of the project. I'm inclined to close this as wontfix. How big of an issue is it?

[mkoeppe]

How big of an issue is it?

It's critical because it makes it impossible for another Python project to declare a dependency on fpylll.

[malb]

Okay, the PR referenced above should do what is needed.