Since code in trunk branch has been ported to Python 3, we also need to port `make lint` to Python 3, essentially to the pep8 and pyflakes utilities. As we know that command pep8 and pyflakes, that can be found from the directories in environment variable PATH, are used to check. In Fedora (that I'm running now), Python 2.x is still the default version of Python interpreter for system. Although pep8 and pyflakes for Python 3 exist, they are prefixed with python3- in command name individually, therefore they cannot be used along with lint target in make.
One possible solution is that define PEP8 and PYFLAKES macro, that default to pep8 and pyflakes and also allow developer to specify custom ones in the command line. For example,
$ make lint PEP8=python3-pep8 PYFLAKES=python3-pyflakes
Merged in revision 1349