require any binary searching of hlink data.

to output the "filename" value when it might not be initialized.

preliminary patch by J.W.

mutually exclusive based on mode).  Based on an idea by J.W.

receive_file_entry().

send_file_entry() and receive_file_entry().  Other cleanups too.

called by the batch processor.

- Don't transmit the sum array for non-regular files (p28 onward).
- Tweaked a couple comments.

test same, same high and different device numbers.

some of the variable names more logical in the new program flow.  Also
improved the setting of the new last_rdev value that only remembers the
high 3 bytes.

(but only when speaking protocol 28).

- Changed PROTOCOL_VERSION to 28 now.

the SAME_RDEV bit into the next 8 bits and adding an EXTENDED_FLAG
bit.  Also modified the meaning of this bit for protocol 28 and above:
SAME_HIGH_RDEV indicates that all but the lowest byte matches.  The
older protocols get OLD_SAME_RDEV set (with the old semantics) for
compatibility.  Note also that protocol 28 isn't turned on yet.

make it a little easier to read and a little more optimized.  Also
made the flag size in our function calls match the size of the flags
in the flist_struct.  These changes will make it easier for me to
optimize the sending of the hard-link data in a future commit.

- The realloc in init_hard_links() might fail if the list is empty
  (which can happen if there are no regular files in the transfer).
  I changed the code to free the list in that case.