[Bug-XBoard] xboard doesn't detect a server side disconnection in ics-mode

[diffset]

Hi,

when using xboard in ics-mode it doesn't detect a server side
disconnect. E.g. if you write „logout“ in the ics input box or the
attached terminal the logout out screen from fics is displayed and
xboard keeps running with a 100% processor load. Any commands sent to
fics by xboard (e.g. by clicking on the board to see the seek graph)
result is a crash (broken pipe).