% git checkout 34794819d8
% cd lib
% git clean -xdf
% cd ..
% pip install -e .
% pythonw testMac.py

Traceback (most recent call last):
  File "testMac.py", line 3, in <module>
    import matplotlib.pyplot as plt
  File "/Users/jklymak/matplotlib/lib/matplotlib/pyplot.py", line 2410, in <module>
    switch_backend(rcParams["backend"])
  File "/Users/jklymak/matplotlib/lib/matplotlib/pyplot.py", line 246, in switch_backend
    backend_mod = importlib.import_module(backend_name)
  File "/Users/jklymak/anaconda3/envs/matplotlibdev/lib/python3.6/importlib/__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "/Users/jklymak/matplotlib/lib/matplotlib/backends/backend_macosx.py", line 14, in <module>
    from matplotlib.backends import _macosx
ImportError: Python is not installed as a framework. The Mac OS X backend will not be able to function correctly if Python is not installed as a framework. See the Python documentation for more information on installing Python as a framework on Mac OS X. Please either reinstall Python as a framework, or try one of the other backends. If you are using (Ana)Conda please install python.app and replace the use of 'python' with 'pythonw'. See 'Working with Matplotlib on OSX' in the Matplotlib FAQ for more information.