Complete a set of OPTIONS, each beginning with PREFIX (?- by default).
PREFIX may be t, in which case no PREFIX character is necessary.
If NO-GANGING is non-nil, each option is separate (-xy is not allowed).
If ARGS-FOLLOW is non-nil, then options which take arguments may have
the argument appear after a ganged set of options. This is how tar
behaves, for example.
Arguments NO-GANGING and ARGS-FOLLOW are currently ignored.
(fn OPTIONS &optional PREFIX NO-GANGING ARGS-FOLLOW)