INT 21 - DOS 3.1+ network - CANCEL REDIRECTION
        AX = 5F04h
        DS:SI -> ASCIZ local device name or path
        CX = 4E57h ("NW") for NetWare 4.0 requester
Return: CF clear if successful
        CF set on error
            AX = error code (01h,03h,05h,08h,0Fh,12h) (see AH=59h)
Notes:  the DS:SI string must be either a local device name, a drive letter
          followed by a colon, or a network directory beginning with two
          backslashes
        the DOS kernel calls INT 2F/AX=111Eh with AX on top of the stack
        also supported by Banyan VINES, LANtastic, and 10NET
SeeAlso: AX=5F03h,INT 2F/AX=111Eh

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