* src/getargs.c (usage): Take status as argument and exit

* src/getargs.c (usage): Take status as argument and exit
accordingly.
Report the traditional `Try ... --help' message when status != 0.
(usage, version): Don't take a FILE * as arg, it is pointless.
(getargs): When there is an incorrect number of arguments, make it
an error, and report it GNUlically thanks to `usage ()'.