GMT/UTC.

Added special log output to ftp_close_socket when closing the server socket.
Rearranged termination sequence at end of ctrl_thread to fix race conditions.
Added wait at end of ftp_server thread for other threads to terminate

using dynamically allocated xfer_t buffer rather than static local variable.

"restarted" after accept failure or possibly via semaphore (soon).

Added send_thread and filexfer debug bits.

transfer to complete.

first result.

Hopefully solves problem of asynchronous log output during sbbsctrl shutdown.

matchuser() now optionally matches built-in sysop aliases.

and other potential multi-threaded issues.

Added use of select to receive_thread to solve possible dead-lock during uploads.
Moved periodic transfer progress reports to occur even when no data is transferring.
Changed all byte value printfs to unsigned and all sockets to signed.

If resuming transfer, offset is now shown in progress reports.

Eliminated exception in send_thread() when shut-down during transfer
by no-longer dereferencing ctrl_thread pointer if shut-down in progress.

Fixed up the "waiting for transfer to complete" section to abort if server is shut-down (dangerous?) and not to disconnect over-and-over.