INT 2F - Novell DOS 7+ FDOS EXTENSIONS - ALLOCATE CLUSTER

	AX = 1005h
	BX = block from which to start search (e.g. current end of file)
	    0000h = start of disk
Return: AX or BX??? = allocated cluster (already marked as End of Chain)
	    or 0000h if none available
Notes:	This private function is called internally by the OS kernel to
	  ask the FDOS to allocate disk space.  By using the
	  INT 2F/AX=1001h FDOS hook, the call can be intercepted by external
	  system components such as the DELWATCH TSR.
	This function must under no circumstances be called by applications!
SeeAlso: INT 2F/AX=1001h,AX=1004h,AX=1007h,AX=10FEh