In gnuradio-core/src/lib/filter, generate.py and others invoke python as python, rather than using the path where configure found python. This fails on systems that install python as pythonX.Y and do not provide a default symlink from python; an example system where this approach results in a build failure is pkgsrc.

There is a related issue about installing scripts that point to the python found at install time, but this ticket is about the build failure.

One fix is to move all the .py files to .py.in and replace "/usr/bin/env python" with "PYTHON".