Add buildtool depend on setuptools

[sloretz]

Requires ros/rosdistro#23532
See http://build.ros.org/job/Ndev__genmsg__ubuntu_focal_amd64/2/console

This seems to be python3 specific. I don't see a python-distutils package for python 2 in Debian or Ubuntu. It looks like every package importing distutils in its setup.py will need to depend on this. Maybe catkin should export the dependency instead?

[dirk-thomas]

How about changing the import to setuptools instead which has been the Python recommendation for a long time (and add the necessary dependency to the manifest)?

[sloretz]

How about changing the import to setuptools instead

Is 6b4755f what you had in mind?

[dirk-thomas]

It likely needs a Python 2 dependency for setuptools too.

[sloretz]

It likely needs a Python 2 dependency for setuptools too.

e18244b

[dirk-thomas]

(Doh, I should have changed the title before the merge...)