search for: io_multiplexing_writ

Hello, The attached patch should fix Debian bug #128632 (http://bugs.debian.org/128632). This bug happened because if an error occurred in writefd_unbuffered (such as the remote end closing the socket), it would call rprintf, which would call io_multiplexing_write, which would in turn call writefd_unbuffered, which would then just sit in a loop trying to write to the broken socket. Also, we have to ignore SIGPIPE; it is better to handle an EPIPE return code. Otherwise we end up calling rprintf inside the sigint handler, and we're back in the same boat...