INT 21 - MS-DOS 7.0+ - GENERIC IOCTL - GET FIRST CLUSTER

	AX = 440Dh
	CX = 0871h / 4871h
	    (category code 08h for FAT12/16, 48h for FAT32; minor code 71h)
	BX = filename character set (see #01578)
	DS:DX -> ASCIZ pathname for file or directory
Return: CF set on error
	    AX = error code (01h,02h,etc.) (see #01680 at AH=59h/BX=0000h)
	CF clear if successful
	    DX:AX = first cluster number
Note:	this function finds any file or directory regardless of attributes,
	  except that it will not find volume labels
SeeAlso: AX=440Dh"DOS 3.2+",AX=440Dh/CX=086Ch,#01352