condition if called with an initial string longer than the specified
size limit (due to an unsigned var's inability to go negative).

a potential problem in the batch-filename code).

send a truncated filename.

local_exclude_list, not the exclude_list.

vanished-file message (not FINFO).

- Got rid of FNONE from logcode enum.
- Created msgcode enum with MSG_DATA, MSG_REDO, MSG_DONE, etc.

- Use new send_msg() call with MSG_DONE or MSG_REDO.

- Got rid of the recv_pipe between the receiver and the generator.
- Use new send_msg(MSG_DONE,...) call to signal the generator
  when the receiver is done.
- Use the new get_redo_num() call in the generator to read the
  final -1 from the receiver.

- Call the new send_msg() function to send a remote log message.

- Renamed log_error_fd to msg_fd_out, and io_error_fd to msg_fd_in.
- Added a redo_list* to keep track of any redo items that come over
  the message channel from the receiver to the generator.
- The io_flush() and msg_list_push() functions now take an arg:
  NORMAL_FLUSH or FULL_FLUSH.  The latter ensures that we don't lose
  any log messages that haven't gotten written from the msg_list.
- Added a send_msg() function that log.c calls to send any remote
  log messages.  It is also called to send the new MSG_REDO and
  MSG_DONE messages.

the error now says that chgrp failed, not chown.

and no permissions to set group 0.

when using --progress.

right spot, and moved some externs.