Brett or Eric, any chance one of you could run with this for 3.7b3? I already have a startup refactoring related regression that I'm aiming to have fixed before then.

Thanks to Victor's refactoring work, there's at least a clear interception point now where we can treat the empty string differently depending on whether the command line option was `-c`, `-m`, or not specified at all: https://github.com/python/cpython/blob/master/Python/pathconfig.c#L259

As an initial attempt, I think the necessary fix will be along the lines of checking for 'n == 0 && argc > 1 && wcscmp(argv0, L"-m") == 0', and resolving the current working directory in that case.