INT 21 - Banyan VINES 2.1+ - SET EXTENDED FILE ATTRIBUTES
        AX = 43100h
        CH = new attributes
            bit 7: unused
            bit 6: shareable
            bit 5: execute-only
            bits 4-0: unused
        DS:DX -> ASCIZ filename
Return: CF clear if successful
        CF set on error
            AX = error code (01h,02h,03h,05h) (see AH=59h)
Note:   the filename may be a directory but must be on a VINES file service
SeeAlso: AX=4310h,INT 2F/AX=110Eh