* net/tramp.el (tramp-methods): New method "rsyncc".

* net/tramp.el (tramp-methods): New method "rsyncc".
(top): Add completion function for "rsyncc".
(tramp-message-show-message): New defvar.
(tramp-message, tramp-error): Use it.
(tramp-do-copy-or-rename-file-directly): Extend check for direct
remote copying.
(tramp-do-copy-or-rename-file-out-of-band): Handle new
`tramp-methods' entry `copy-env' of "rsyncc".
((tramp-handle-process-file): Do not flush all
caches when `process-file-side-effects' is set.
tramp-vc-registered-read-file-names): New defconst.
(tramp-vc-registered-file-names): New defvar.
(tramp-handle-vc-registered): Implement optimization strategy.
(tramp-run-real-handler): Add `tramp-vc-file-name-handler'.
(tramp-vc-file-name-handler): New defun.
(tramp-get-ls-command, tramp-get-test-command)
(tramp-get-file-exists-command, tramp-get-remote-ln)
(tramp-get-remote-perl, tramp-get-remote-stat)
(tramp-get-remote-id): Remove
superfluous `with-current-buffer'.