INT 7A - Novell NetWare - IPXODI v2.12+ - OPEN LOOK-AHEAD SOCKET

	BX = 0023h
	DX = socket number (0000h for dynamic allocation)
	ES:SI -> Look Ahead handler (see #03831)
	BP = desired lookahead size (0000h-0080h)
Return: AL = status
	    00h successful
		DX = assigned socket number (big-endian)
	    FEh maximum number of sockets already open
	    FFh specific socket already opened by another application
	DS,FLAGS preserved
	all other registers may be destroyed
Notes:	the socket will always be long-lived, and must thus be explicitly
	  closed with INT 7A/BX=0001h before the Look Ahead handler code is
	  removed from memory (i.e. the program terminates)
	this function is only supported if INT 2F/AX=7A00h returns ES:BX
	  pointing at an IPX version greater than 3.30
	the desired lookahead size is the smallest-size packet (including IPX
	  header) that should be passed to the lookahead handler when it
	  arrives
SeeAlso: INT 7A/BX=0000h,INT 7A/BX=0001h