Here is a patch that adds a test of the underlying problem and fixes it.  I don't like this patch because it tries to detect the line ending style of the input stream and changes behavior based on that, but because email wants to use '\n' as the separator internally I don't see another way to fix it at the moment.  The ugliest part is that I changed the expected result of one existing test...but that test uses an artificial way of opening an input file in order to test the parser's universal newline handling, and I think the behavior tested is arguably incorrect.

I'm not sure this will fix all the windows failures, but it should fix most of them.