MQTT_PAL_MSG_NOSIGNAL

[ozlb]

• Handle SIGPIPE on socket disconnected in non windows platforms
• Set MQTT_ERROR_RECONNECTING on send/receive error and consecutive timeouts

[yamt]

• you should exclude whitespace changes.
• don't assume the value or existence of MSG_NOSIGNAL.
• the commit message ("Add files via upload", "handle Segmentation fault", ...) doesn't make sense.