INT 21 - Windows95 - LONG FILENAME - CREATE SUBST                               
	AX = 71AAh
	BH = 00h
	BL = drive number (00h = default, 01h = A:, etc.)
	DS:DX -> ASCIZA NUL-terminated ASCII string.	The ASCIZ string "ABC" consists of the four bytes 41h, 42h, 43h, and 00h.  Unless otherwise specified, maximum lengths given in the interrupt list do not include the terminating NUL. pathname to associate with drive letter
Return: CF clear if successful
	CF set on error
	    AX = error code (see #01680)
		7100h if function not supported
SeeAlso: AX=71AAh/BH=01h,AX=71AAh/BH=02h,INT 2F/AX=1000h,#01643