freetdm: ISDN-Fix for d-channel indexing, causing improper configuration on non-consecutive logical spans

fix seg related to ptime mismatch + CNG + PLC (if you ever get purple ptime mismatch warnings you want this patch)

treat EINTR returns as a BREAK (now mapped to SWITCH_STATUS_INTR), we appriciate the interrupted syscalls but we would like to continue working properly

         otherwise the channel name is not set in 'show channels'

merge code from xml-rpc trunk - fix xml-rpc not terminating on windows on fs unload - only effect windows build