back to the function via the calls that it is making.  The new code
treats each recursion back into the function as an opportunity to
take up where we left off (skipping whatever step just failed).

recursion-prevention heuristic in _exit_cleanup().

file needed to check that cleanup_fname was not NULL to prevent
any possibility of a recursion starting into that code again.

to silence a code-checker warning.

- Changed two last strcpy() calls to strlcpy() calls.

- Added a default: exit_cleanup() case to a switch.
- Made the check_name() function take a buffer size arg.

  to get rid of code that is not needed on the current system.
- Silence a code-checker warning in send_file_entry().
- Silence a code-checker warning in make_file().
- Fixed a bug in f_name_cmp() that could compare an empty filename
  incorrectly (which might only happen if we transformed a dot-dir
  into an empty name).  (Thanks, code checker!)

can analyze some of the other programs (since it runs out of
time analyzing them all).

calling exit_cleanup() (which is a safer way to avoid an infinite
loop when the exit code uses the log functions than allowing the
_exit_cleanup() function to return back into our code).

- Mark _exit_cleanup() with NORETURN.
- Don't ever return from _exit_cleanup().

- Added a NORETURN define to mark a function that never returns.

to get_tmpname().

(so we don't need to keep adding variable-type strings).

to to substitute a chmod that will work everywhere.

- Cleaned up some trailing whitespace.

longer for MAXPATHLEN.  Also fixed a couple spots nearby that were
erroneously treating pointer "cp" as a '\0'-terminated string.