INT 21 - DR-DOS 3.41+ internal - GET ACCESS RIGHTS
        AX = 4302h
        DS:DX -> ASCIZ pathname
Return: CF clear if successful
            CX = access rights
                bit 0 owner delete requires password
                bit 1 owner execution requires password (FlexOS)
                bit 2 owner write requires password
                bit 3 owner read requires password
                bit 4 group delete requires password
                bit 5 group execution requires password (FlexOS)
                bit 6 group write requires password
                bit 7 group read requires password
                bit 8 world delete requires password
                bit 9 world execution requires password (FlexOS)
                bit 10 world write requires password
                bit 11 world read requires password
            AX = CX (DR-DOS 5.0)
        CF set on error
            AX = error code
Desc:   Determine which operations the calling program may perform on a
          specified file without being required to provide a password.
Notes:  this protection scheme has been coordinated on all current Digital
          Research/Novell operating systems (DR-DOS 3.41+, DRMDOS 5.x, and
          FlexOS 2+)
        only FlexOS actually uses the "execution" bits; DR-DOS 3.41+ treats
          them as "read" bits.
        DR-DOS 3.41-5.x only use bits 0-3.  Only DR-DOS 6.0 using a
          DRMDOS 5.x security system allowing for users and groups uses bits
          4-11.