Both client and server C code have a lot of historical baggage for very old UNIX systems. I'd like to remove some of that, as the baggage makes ongoing maintenance a little harder than it could be. For instance, I recently removed RETSIGTYPE from COW because autoconf's autoupdate suggested it was no longer required. Pull requests welcome. I don't wish to appear to be focused on Linux, but I only test on Linux so if you have a favourite UNIX or UNIX-like operating system, please get involved.