su syntax

[Davide Marchignoli]

Dear mantainer,

Running 
        su -c echo davide -norc
with su (in sh-utils 2.0) under linux I receive the following

        su: invalid option -- n
        Try `su --help' for more information.

is this correct?
Reading the usage it seemed (to me) that the -norc option went to the
shell, instead here it is parsed by getopt.

Best Regards,

                        Davide Marchignoli