As of 1.5.0, the stream operators are only declared for the class LinuxServer, the base class LinuxSocket might need the same operators.
I reworked the LinuxServer/LinuxSocket classes to move the << and >> operators from LinuxServer to LinuxSocket. By the way, LinuxServer::accept requires a LinuxSocket argument (this change might break other code).
Proposed patch is attached to this report. It is based on revision 77.