Installing backshift with configure+make:

1. Download the code or check it out.
2. Configure (below are three ways, pick one of the three):
   • Use Pypy3 - fast, and appears pretty much bugless in recent versions
     • ./configure --python /usr/local/pypy3-2.4.0/bin/pypy3
   • Use CPython 3.x - slow, but makes use of the reference implementation of Python
     • ./configure --python /usr/bin/python3
   • Use CPython 3.x with Cython - a bit faster
     • ./configure --python /usr/bin/python3 --use-cython
3. Install
   • make install
4. Backshift should now appear in /usr/local/bin.
5. You can also give "./configure --prefix /usr" or similar, to change where backshift gets installed. By default, it goes under /usr/local.