[Python-ideas] site.py uses os.sep to determine platform

[Alex Walters]

On august 7th, 1998, Guido committed
https://github.com/python/cpython/commit/d89fa0c5761254c970af72e5abcea420fd2
3e893 to python, adding the quit() and exit() built-ins.  He decided to
determine the platform python was running on by checking os.sep.  I don't
understand the rationale behind this choice in 1998, but I assume that there
was one.

It's 2017.  We have sys.platform, and the standard library is tested against
everything that vanilla cpython (unpatched by a vendor) will ever put in
cpython.

Is there any reason not to change os.sep == '\\' to sys.platform == 'win32'
in 2017?