* doc/misc/tramp.texi (External packages): Don't use Tramp internals. * lisp/net/tramp-gvfs.el (tramp-gvfs-handler-mounted-unmounted): Protect `tramp-make-tramp-file-name' call. * lisp/net/tramp.el (tramp-make-tramp-file-name): Set advertised calling conventions. * test/lisp/net/tramp-tests.el (tramp-test18-file-attributes): Adapt test. (tramp--test-supports-processes-p): New defun. (tramp-test28-process-file, tramp-test29-start-file-process) (tramp-test30-make-process, tramp-test32-shell-command) (tramp-test32-shell-command-dont-erase-buffer) (tramp-test34-explicit-shell-file-name, tramp-test35-exec-path) (tramp-test44-asynchronous-requests): Use it.