SYNOPSIS
	void dangling_lfun_closure()

DESCRIPTION
	Handle a dangling lfun-closure.

	This is called when the gamedriver executes a closure using a
	vanished lfun. A proper handling is to raise a runtime error.

	Technical:
	  Upon replacing programs (see efun replace_program()), any
	  existing lambda closures of the object are adjusted to the
	  new environment. If a closure uses a lfun which vanished in
	  the replacement process, the reference to this lfun is
	  replaced by a reference to this function. The error will
	  then occur when the execution of the adjusted lambda reaches
	  the point of the lfun reference. There are two reasons for
	  the delayed handling. First is that the program replacement
	  and with it the closure adjustment happens at the end of a
	  backend cycle, outside of any execution thread: noone would
	  see the error at this time.  Second, smart closures might
	  know/recognize the program replacement  and skip the call to
	  the vanished lfun.

SEE ALSO
	closures(LPC)