scons-python3 bootstrap.py broken

Attempting to run via bootstrap.py:

 python3 ~/scons-py3/bootstrap.py
/home/nbecker/anaconda3/envs/py35/bin/python3 /home/nbecker/scons-
py3/bootstrap/src/script/scons.py
Import failed. Unable to find SCons files in:
  /home/nbecker/scons-py3/bootstrap/src/engine
  /home/nbecker/scons-py3/bootstrap/src/script/../engine
  /home/nbecker/scons-py3/bootstrap/src/script/scons-local-__VERSION__
  /home/nbecker/scons-py3/bootstrap/src/script/scons-local
  /home/nbecker/anaconda3/envs/py35/lib/scons-__VERSION__
  /home/nbecker/anaconda3/envs/py35/lib/python3.5/site-packages/scons-
__VERSION__
  /home/nbecker/anaconda3/envs/py35/lib/scons-__VERSION__
  /home/nbecker/anaconda3/envs/py35/lib/scons
  /home/nbecker/anaconda3/envs/py35/lib/python3.5/site-packages/scons
  /home/nbecker/anaconda3/envs/py35/lib/scons
Traceback (most recent call last):
  File "/home/nbecker/scons-py3/bootstrap/src/script/scons.py", line 190, in 
<module>
    import SCons.Script
  File "/home/nbecker/scons-
py3/bootstrap/src/engine/SCons/Script/__init__.py", line 88, in <module>
    from . import Main
  File "/home/nbecker/scons-py3/bootstrap/src/engine/SCons/Script/Main.py", 
line 370
    except OSError, e:
                  ^
SyntaxError: invalid syntax

Something is rewriting Main.py.  If I manually fix it, then re-run 
bootstrap.py Main.py gets re-written with syntax errors.