c modules compiled at first execution, not install

The c modules are compiled at the first execution, not at install time.  For a site-wide install (as admin/root), the execution (in userland) fails unless admin/root access is granted.  No issue in a virtualenv.

Install method tested (ubuntu 22.04): `sudo -H pip3 install pyreduce-astro`.  First run must use: `sudo python3`.