I think that platform-specific members of module should be either hidden (as done in this patch) or renamed to something like WINDOWS_PATH_SEPARATOR1 and UNIX_PATH_SEPARATOR and made available on all platforms.
I agree completely—if a module deals with platform-specific details, it should try to hide them completely. The current API divergence in io.paths is gross and should be eliminated.
I think that platform-specific members of module should be either hidden (as done in this patch) or renamed to something like WINDOWS_PATH_SEPARATOR1 and UNIX_PATH_SEPARATOR and made available on all platforms.