Use POSIX "df" in Tramp, if available
* lisp/net/tramp-sh.el (tramp-get-remote-df): Support also POSIX.1 "df". (tramp-sh-handle-file-system-info): Adapt accordingly.
* lisp/net/tramp-sh.el (tramp-get-remote-df): Support also POSIX.1 "df". (tramp-sh-handle-file-system-info): Adapt accordingly.