When using support/rrsync (rsync-3.0.4), if server-side options look like
  "--server -e.<whatever>"
the script fails, leading to a client-side message like this:

rsync: connection unexpectedly closed (0 bytes received so far) [sender]
rsync error: unexplained error (code 255) at io.c(632) [sender=3.0.4]

This does not appear to happen when the 'e' follows other characters on the
server side. For example, "rsync -a file rem:." on the client side results in
arguments that look like this on the server: "--server -logDtpre.iLs . .".
In this case, everything is fine.  On the other hand, if you try
"rsync file rem:." on the client side, the arguments on the server look
like this: "--server -e.Ls . .", and it fails.

I believe the problem is on line 147 of support/rrsync.  If I change it from
      next if /^-$short_no_arg+(e\d*\.\w*)?$/o || /^-$short_with_num\d+$/o;
to
      next if /^-$short_no_arg*(e\d*\.\w*)?$/o || /^-$short_with_num\d+$/o;

the problem appears to go away.

Thanks,
George