SYNOPSIS
	int add_weight(int w)

DESCRIPTION
	In compat mode, this function is used by the efun transfer().

	An object that can contain other objects and is not a room
	must define this function. It is called with the extra weight
	of the object that is moved into it. If this is ok, then it
	has to increment the local weight count, and return true.
	Otherwise, return false, and the new object can not be entered
	into this object.

	The function is also called with the negative weight in the
	object that the moving leaves.
	
	Note that no set_weight() is required by the parser.

SEE ALSO
	transfer(E), query_weight(A), prevent_insert(A)