[pycrypto] Once again: Python3 with PyCrypto

[Thorsten Behrens]

Quick update on where this stands right now.

As predicted, the module handling changes with Python 3.x were a pain. I 
think I have them under control now. At least "python setup.py test" no 
longer crashes immediately. It now gets far enough to complain about 
bytes/unicode errors.

I haven't attempted _fastmath.c on Python 3.x yet. I'll do that last, 
when everything else works.

C modules will give link-time errors, like so: "_counter.obj : warning 
LNK4197: export 'init_counter' specified multiple times; using first 
specification". This is an issue in distutils. See python issue 9709. 
There's nothing we can do until Python fixes distutils - of course any 
pre-compiled binaries can be built with the distutils fix in, and the 
README can warn people of this.

The code still works with Python27, but I broke Python21. Specifically, 
I am having a hard time with string literals. The main work remaining 
now is to flush out string to bytes/unicode changes between 2.x and 3.x, 
and adapt the code. I thought I had this licked, but I clearly don't.

I am currently not handling literals well. This is what I tried:
         if sys.version_info[0] is 2:
             seed = "".join(seed)
         else:
             seed = b"".join(seed)

And that gives a "SyntaxError: invalid syntax" at run time. Of course it 
does.

django has been moved to be 2.x/3.x compatible. I'll see what they did 
and try to replicate it. I'm hoping it'll take care of these type of issues.

Assignment to True and False in pycrypto_compat.py is an issue. Right 
now, I just don't import pycrypto_compat.py when Python 3.x is detected. 
That still gives install-time errors on Python 3.x. The only option I 
can think of right now is to exclude the offending file from install in 
setup.py if Python 3.x is detected.

Thorsten